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 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 27  |  Issue : 4  |  Page : 766-774

Effect of pentoxifylline and pioglitazone on rheumatoid arthritis induced experimentally in rats


1 Department of Pharmacology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
2 Department of Pharmacology, Benha University Hospitals, Benha, Egypt

Date of Submission23-Dec-2014
Date of Acceptance09-Apr-2014
Date of Web Publication22-Jan-2015

Correspondence Address:
Asmaa M Rezk
Benha University Hospitals, Benha
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1110-2098.149748

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  Abstract 

Objective
To investigate the effect of pentoxifylline (PTX) and pioglitazone (Pg), each alone and in combination with methotrexate (MTX), on rheumatoid arthritis (RA) induced experimentally in male albino rats.
Background
Individuals have long feared RA as one of the most disabling types of arthritis. It is estimated that over 46 million individuals have arthritis, ~1% worldwide.
Material and methods
One hundred and eighty adult male albino rats were used in the present study. MTX was administered intraperitoneally at a dose of 0.25 mg/kg daily. PTX was administered intraperitoneally at a dose of 150 mg/kg/rat/day, whereas Pg was administered orally at a dose of 3 mg/kg/day. All doses were administered for a period of 2 weeks. RA was induced by two methods: adjuvant-induced arthritis and pristane-induced arthritis (PIA). Adjuvant-induced arthritis was induced by an intradermal injection of 0.1 ml of complete Freund adjuvant. This type of arthritis appears about 8-12 days after injection. PIA was induced by a single intradermal injection with 0.2 ml pristane at the base of the tail. PIA develops in 2-3 weeks after injection and progresses with a relapsing course that persists for months.
Results
The anti-inflammatory properties of these drugs were confirmed by reduction of erythrocyte sedimentation rate, serum rheumatoid factor level, serum C-reactive protein level, serum tumor necrosis factor-a level, serum nitrite level, and blood superoxide dismutase level, whereas antioxidant activities were confirmed by an increase in the blood reduced glutathione level. Our study showed that Pg alone exerts portentous effects in the treatment of RA. However, it was more active in combination with MTX.
Conclusion
Our study showed that Pg was the most potent drug in treating arthritic rats, followed by PTX, with lesser potency in treating arthritic rats. When comparing the two combinations, the combination of Pg with MTX was the most potent one. The second combination was the combination of PTX with MTX.

Keywords: Complete Freund adjuvant, methotrexate, pentoxifylline, pioglitazone, pristine, rheumatoid arthritis


How to cite this article:
Mohamed MA, Mahmoud MF, Rezk AM. Effect of pentoxifylline and pioglitazone on rheumatoid arthritis induced experimentally in rats. Menoufia Med J 2014;27:766-74

How to cite this URL:
Mohamed MA, Mahmoud MF, Rezk AM. Effect of pentoxifylline and pioglitazone on rheumatoid arthritis induced experimentally in rats. Menoufia Med J [serial online] 2014 [cited 2020 Feb 17];27:766-74. Available from: http://www.mmj.eg.net/text.asp?2014/27/4/766/149748


  Introduction Top


Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory, autoimmune disease, characterized by synovial hyperplasia with massive infiltration of inflammatory cells in the affected joints, leading to degeneration of cartilage and erosion of bone, and ultimately causes functional loss of joints. It is a disease of unknown etiology and it is widely believed that an infectious agent or another foreign immunologic stimulus triggers the disease, which is characterized by self-damaging inflammation and immunologic autoreactivity [1]. The early recognition and treatment of RA is important to minimize disability and maximize quality of life, and any delay in treatment of just a few months can result in significantly more joint damage subsequently during the course of disease [2].

Management of patients with RA involves patient education, physical and occupational therapy, and administration of disease-modifying antirheumatic drugs. Methotrexate (MTX) is presently the preferred disease-modifying antirheumatic drug for patients with active RA because of its long-term effectiveness in clinical practice [3]. MTX is a potent antimetabolite inhibiting purine synthesis enzyme dihydrofolate reductase, which subsequently inhibits de-novo purine and pyrimidine synthesis. Known to be the cornerstone of disease-modifying treatment in patients with RA, it is one of the most successfully used antirheumatic agents [4].

Pentoxifylline (PTX) is a xanthine derivative with the chemical name 1-(5-oxohexyl)-3,7-dimethylxanthine [5]. PTX downregulates the production of proinflammatory cytokines, particularly tumor necrosis factor-a (TNF-a), in response to noxious stimuli [6]. PTX also attenuates the toxic effect of TNF-a. However, the mechanism underlying PTX-induced cytoprotection is unknown [7]. Pioglitazone (Pg), a thiazolidinedione derivative drug, is a useful glucose-lowering agent for patients with type 2 diabetes, in monotherapy and in combination with a sulfonylurea, metformin, or insulin. Through PPAR-g-mediated effects, these drugs not only improve insulin sensitivity and glycemia but also exert beneficial effects on lipid metabolism. Being a PPAR-g agonist, it has been shown to be effective in reducing inflammation in Parkinson's disease models; levels of MMPs and microglia (therefore, TNF-a and other cytokine levels) were found to be reduced [8].

In this study, we investigate the effect of PTX and Pg, each alone and in combination with MTX, on RA induced experimentally in male albino rats.


  Materials and methods Top


Animals

The study was carried out on adult male albino rats weighing about 150-200 g obtained from the National Research Center (Cairo, Egypt). The animals were housed in polystyrene cages (seven rats/cage) containing wood shaving bedding. They were kept at a constant temperature of 25 ± 2°C and illumination (12 h light/dark) throughout the experiment. They were fed standard chow diet and were provided free access to tap water.

Chemicals

Complete Freund adjuvant (CFA) was obtained from Sigma-Aldrich (USA). Pristane was also supplied by Sigma-Aldrich. PTX was obtained from Sigma-Aldrich, and was freshly prepared in saline obtained from EL-Gomhouria Co. (Zagazig, Egypt). Pg was supplied by Amoun (Egypt) and was freshly prepared in 2% Tween 80 obtained from EL-Gomhouria Co. MTX was supplied by the United Company for Distribution (Cairo, Egypt) and was dissolved in saline obtained from EL-Gomhouria Co. Kits for measuring C-reactive protein (CRP) were supplied by eBioscience (UK); for glutathione (GSH), nitric oxide (NO) and superoxide dismutase (SOD) were obtained from Bio Diagnostic Co.; rheumatoid factor (RF) was supplied by MyBiosource (USA); and TNF-a was obtained from Bender MedSystems GmbH (Europe).

Induction of rheumatoid arthritis

RA was induced by two methods: adjuvant-induced arthritis and pristane-induced arthritis (PIA). Adjuvant-induced arthritis was induced by an intradermal injection of 0.1 ml of CFA containing 10 mg/ml Mycobacterium butyricum or Mycobacterium tuberculosis products. This type of arthritis appears about 8-12 days after injection [9]. PIA was induced by a single intradermal injection with 0.2 ml pristane at the base of the tail. PIA develops in 2-3 weeks after injection and progresses with a relapsing course that persists for months [10].

Experimental design

After a 2-week adaptation period, rats were assigned randomly to two main groups. Group A arthritis was induced by CFA and was subdivided as follows: Subgroup A1 included nonarthritic control rats that received only saline by an oral gavage and Subgroup A2 included arthritic control rats administered only 0.1 ml CFA once each; Subgroup A3 included arthritic rats that received MTX (0.25 mg/kg) intraperitoneally for 10 days and represented the treated-control group; Subgroup A4 included arthritic rats that received PTX (150 mg/kg/rat/day) intraperitoneally for 2 weeks; Subgroup A5 included arthritic rats that received Pg (3 mg/kg/day) orally for 2 weeks; Subgroup A6 included arthritic rats that received a combination of PTX (150 mg/kg/rat/day) orally and MTX (0.25 mg/kg) intraperitoneally daily for 2 weeks; and Subgroup A7 included arthritic rats that received combination of Pg (3 mg/kg) orally and MTX (0.25 mg/kg) intraperitoneally daily for 2 weeks. In Group B, arthritis was induced by a single intradermal injection with 0.2 ml pristane at the base of the tail, and was subdivided as follows: Subgroup B1 included nonarthritic control rats that received only saline by an oral gavage; Subgroup B2 included arthritic control rats that were administered only 0.1 ml CFA once each; Subgroup B3 included arthritic rats that received MTX (0.25 mg/kg) intraperitoneally for 10 days and represented the treated-control group; Subgroup B4 included arthritic rats that received PTX (150 mg/kg/rat/day) intraperitoneally for 2 weeks; Subgroup B5 included arthritic rats that received Pg (3 mg/kg/day) orally for 2 weeks; Subgroup B6 included arthritic rats that received a combination of PTX (150 mg/kg/rat/day) orally and MTX (0.25 mg/kg) intraperitoneally daily for 2 weeks; and Subgroup B7 included arthritic rats that received a combination of Pg (3 mg/kg) orally and MTX (0.25 mg/kg) intraperitoneally daily for 2 weeks.

Assessment of arthritis

The development of arthritis was monitored using a macroscopic scoring system for the four limbs ranging from 0-4 (1 = swelling and redness of one joint, 2 = two joints involved, 3 = more than two joints involved, and 4 = severe arthritis in the entire paw). The scores of the four paws were added, yielding a maximum total score of 16 for each rat [11].

Blood sampling and serum preparation

At the end of the study period, blood samples were collected from the retro-orbital venous plexus of rats using microcapillary tubes according to the method of Schemer [12]. Part of the fresh blood sample was used for the detection of the erythrocyte sedimentation rate (ESR). Another part was heparinized and used immediately for the detection of reduced GSH level. Also, part was heparinized and treated with EDTA and then washed and subjected to other special treatments for determination of the SOD level. The rest of the blood was collected in clean dry glass centrifuge tubes and centrifuged at 3700 rpm for 20 min at room temperature using a Heraeus Labofuge 200 centrifuge. The serum was separated, frozen, and stored at −20°C for further biochemical analysis.

Biochemical analysis

Erythrocyte sedimentation rate

0ESR was determined using the ESR Fast Detector according to the principle of Perkins [13].

Rheumatoid factor

RF was determined using an immunoenzymatic assay according to the principle of Cook and Angello [14].

C-reactive protein

CRP was determined using an enzyme-linked immunosorbent assay as described by Nathan and Scheld [15].

Tumor necrosis factor-a

TNF-awas determined using an enzyme-linked immunosorbent assay according to the principle of Takahashi et al. [16].

Nitrite

Nitrite was determined using a colorimetric method as described by Montgomery and Dymock [17].

Superoxide dismutase

SOD was determined using a colorimetric method according to the principle of Nishikimi et al. [18].

Glutathione

GSH was determined using a colorimetric method as described by Beutler et al. [19].

Statistical analysis

All values were expressed as mean ± SEM. Statistical analysis was carried out using both GraphPad Prism version 6 and GraphPad InStat version 3 (GraphPad Software, San Diego, California, USA). The intergroup variation was measured by one-way analysis of variance, followed by the Tukey's test for multiple comparisons as a post-hoc test. A value of P less than 0.05 was used as the limit for statistical significance.


  Results Top


Complete Freund adjuvant

[Table 1] and [Figure 1] show that CFA induced a significant increase in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level and a significant decrease in blood GSH level after 14 days of injection compared with normal rats (P ≤ 0.05). Injection of MTX as a treatment after induction of RA by CFA induced a significant decrease in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level and a significant increase in blood GSH level compared with arthritic rats (P ≤ 0.05).
Figure 1: Effect of treatment with methotrexate (0.25 mg/kg/day intraperitoneally), pentoxifylline (150 mg/kg/day intraperitoneally), and pioglitazone (3 mg/kg orally) each alone and in combination with methotrexate for 2 weeks on serum nitrite (a), blood superoxide dismutase (b), and blood reduced glutathione levels (c) in complete Freund adjuvant-induced arthritic adult male albino rats. *Significantly different from nonarthritic control rats at P < 0.05; @Significantly different from pristane-induced arthritic control rats at P < 0.05.

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Table 1: Effect of treatment with methotrexate (0.25 mg/kg/day intraperitoneally), pentoxifylline (150 mg/kg/day intraperitoneally), and pioglitazone (3 mg/kg orally) each alone and in combination with methotrexate for 2 weeks on some measured parameters in CFA-induced arthritic adult male albino rats

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Administration of both PTX and Pg, each alone as a treatment after induction of RA by CFA, induced a significant decrease in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level and a significant increase in blood GSH level compared with MTX (P ≤ 0.05).

The administration of the two combinations between MTX and drugs under investigations (MTX + PTX) (MTX + Pg), after induction of RA by CFA, elicited a significant decrease in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level, and a significant increase in blood GSH level compared with MTX (P ≤ 0.05).

Pristane

[Table 2] and [Figure 2] show that pristane induced a significant increase in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level and a significant decrease in blood GSH level after 14 days of injection compared with normal rats (P ≤ 0.05). Injection of MTX as a treatment after induction of RA by pristane induced a significant decrease in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level and a significant increase in blood GSH level compared with arthritic rats (P ≤ 0.05).
Figure 2: Effect of treatment with methotrexate (0.25 mg/kg/day intraperitoneally), pentoxifylline (150 mg/kg/day intraperitoneally), and pioglitazone (3 mg/kg orally) each alone and in combination with methotrexate for 2 weeks on serum nitrite (a), blood superoxide dismutase (b), and blood reduced glutathione levels (c) in pristane-induced arthritic adult male albino rats. *Significantly different from nonarthritic control rats at P < 0.05; @Significantly different from pristane-induced arthritic control rats at P < 0.05.

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Table 2: Effect of treatment with methotrexate (0.25 mg/kg/day intraperitoneally), pentoxifylline (150 mg/kg/day intraperitoneally), and pioglitazone (3 mg/kg orally) each alone and in combination with methotrexate for 2 weeks on some measured parameters in pristane-induced arthritic adult male albino rats

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Administration of both PTX and Pg, each alone as a treatment after induction of RA by pristane, induced a significant decrease in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level, and a significant increase in blood GSH level compared with MTX (P ≤ 0.05).

The administration of the two combinations between MTX and drugs under investigations (MTX + PTX) (MTX + Pg), after induction of RA by pristane, elicited a significant decrease in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level and a significant increase in blood GSH level compared with MTX (P ≤ 0.05).


  Discussion Top


Many patients cannot tolerate currently available treatment options for RA. There is thus a significant clinical need for a treatment that is well tolerated and provides rapid relief, and ultimately remission, for RA patients [2].

To achieve our aim, two animal models were used.

Adjuvant-induced arthritis

This type of arthritis, which appears about 8-12 days after injection, is characterized by lymphocyte infiltration into the synovium, cartilage destruction, and bone erosion [9]. Our study confirmed this, that is, arthritis occurred about 9-14 days after the injection of CFA. Yang et al. [20] and Martens et al. [21] also confirmed the findings of our study, in that arthritis appeared 2 weeks after an intradermal injection of CFA. In addition, in the present study, an intradermal injection of CFA into normal male albino rats induced a significant increase in the arthritic index, ESR, serum CRP level, serum RF level, serum TNF-a level, serum nitrite level, and blood SOD level. This result is in agreement with the findings of Mythilypriya et al. [22] and Banji et al. [23], who reported similar results. Meanwhile, in the present study, an intradermal injection of CFA to normal male albino rats induced a significant decrease in blood GSH level. This result is in agreement with the findings of Zheng and Wei [24] and Banji et al. [23], who reported similar results.

Pristane-induced arthritis

This type of arthritis can be induced by an intradermal injection with pristane. PIA develops within 2-3 weeks after injection and progresses with a relapsing course that persists for months [10]. Our study confirmed this, that is, arthritis occurred 2 weeks after an injection of pristane. Furthermore, our study showed that injection of pristane intradermally into normal male albino rats induced a significant increase in the arthritic index, ESR, serum CRP level, serum RF level, serum TNF-a level, serum nitrite level, and blood SOD level. This result is in agreement with the findings of Reeves et al.[25] and Daudin et al. [26], who reported similar results. However, our study showed that injection of pristane intradermally into normal male albino rats induced a significant decrease in blood GSH level. This result is in agreement with the findings of Yao et al. [27] and Daudin et al. [26], who reported similar results.

Drugs of the present study

Methotrexate

This study showed that an intraperitoneal injection of MTX into arthritic rats induced a highly significant decrease in the arthritic index. This finding is in agreement with the observations of Johnston et al. [28] and Xian et al. [4]. In addition, this study showed that an intraperitoneal injection of MTX into arthritic rats induced a highly significant decrease in ESR. This finding is in agreement with the observations of Kay and Westhovens [29]. For serum CRP level, our study showed that an injection of MTX intraperitoneally to arthritic rats showed a highly significant decrease. This finding is in agreement with the observations of Kay and Westhovens [29], who reported similar results. Furthermore, this study showed that administration of MTX intraperitoneally to arthritic rats induced a highly significant decrease in serum RF level. This finding is in agreement with the observations of Halilova et al. [30]. This study showed that intraperitoneal administration of MTX to arthritic rats showed a highly significant decrease in the serum TNF-a level. This finding is similar to the observations of Swierkot et al. [31]. For serum nitrite level, this study showed that intraperitoneal administration of MTX to arthritic rats induced a highly significant decrease. This finding is in agreement with the observations of Tekin et al. [32]. This study showed that an intraperitoneal injection of MTX to arthritic rats induced a highly significant decrease in blood SOD level. This finding is in agreement with the observations of Somi et al. [33]. However, Oguntibeju and Coleshowers [34] reported that the activity of SOD did not differ significantly from the control group after 3 weeks of oral administration of MTX. However, it was significantly altered after 6 weeks of MTX administration. Our study showed that intraperitoneal administration of MTX to arthritic rats induced a highly significant increase in blood GSH level. This finding is in agreement with the observations of Philips et al. [35]. However, Kolli et al. [36] reported that there was a significant decrease in the levels of reduced GSH following MTX treatment.

Pentoxifylline

In the present study, an intraperitoneal injection of PTX to arthritic rats induced a significant decrease in the arthritic index. This result is in agreement with the findings of Rube et al. [6] and Menon et al. [37], who reported similar results. Furthermore, administration of PTX intraperitoneally to arthritic rats induced a highly significant decrease in ESR. This result is in agreement with the findings of Oh et al. [7] and Senolt et al. [38]. Our study also showed that an intraperitoneal injection of PTX to arthritic rats induced a significant decrease in serum CRP level. This result is similar to the findings of Sliwa et al. [39], who showed similar results. In addition, the present study showed that intraperitoneal administration of PTX to arthritic rats induced a significant decrease in serum RF level. This result is in agreement with the findings of Usha et al. [40], who reported similar results. Unsurprisingly, the injection of PTX intraperitoneally, in this study, to arthritic rats induced a highly significant decrease in serum TNF-a level. This result is in agreement with the findings of Sliwa et al. [39] and Gonzαlez-Espinoza et al. [41], who reported similar results. In addition, our study showed that administration of PTX to arthritic rats induced a significant decrease in serum nitrite level. This result is similar to the findings of Stosic´-Grujicic´ et al. [42], who reported similar results. However, Kim et al. [43] observed that PTX significantly augmented nitrite production and iNOS gene expression by interleukin-1b-stimulated vascular smooth muscle cells. However, another research of Trajkoviæ et al. [44] reported that treatment with PTX alone affected neither nitrite production nor iNOS mRNA levels. In addition, in the present study, an intraperitoneal injection of PTX to arthritic rats induced a highly significant decrease in blood SOD level. This result is in agreement with the findings of Keskin et al. [45], who reported similar results. In contrast, the studies of Sema et al. [46] showed that SOD activity was higher in the rats in the PTX-treated group than the control group. The present study also showed that administration of PTX to arthritic rats induced a significant increase in blood GSH. This result is in agreement with the findings of Keskin et al. [45].

Pioglitazone

In this study, oral administration of Pg to arthritic rats induced a highly significant decrease in the arthritic index. These results are in agreement with the findings of Quinn et al. [47], who reported similar results. In addition, administration of Pg orally, in our study, to arthritic rats induced a significant decrease in ESR. These results are in agreement with the findings of Gupta and Gupta [48]. Moreover, administration of Pg orally to arthritic rats induced a highly significant decrease in serum CRP level. These results are in agreement with the findings of Shahin et al. [49] and Zhao et al. [50], who reported similar results. In addition, this study showed that administration of Pg orally to arthritic rats induced a highly significant decrease in serum RF level. These results are similar to the findings of Shahin et al. [49] and Shafaroodi et al. [8]. In this study as well, administration of Pg orally to arthritic rats induced a significant decrease in serum TNF-a level. These results are in agreement with the findings of Enomoto et al. [51] and Shimizu et al. [52], who reported similar results. In addition, oral administration of Pg, in our study, to arthritic rats induced a highly significant decrease in serum nitrite level. These results are in agreement with the findings of Nishio et al. [53] and Xing et al. [54], who reported similar results. Meanwhile, the King et al. [55] study did not confirm any differences in nitrite products or NO levels in patients treated with Pg when compared with placebo for a period of 12 weeks each. Furthermore, this study showed that administration of Pg to arthritic rats induced a significant decrease in blood SOD level. These results are similar to the findings of Hasegawa et al. [56]. However, studies of Medhi et al. [57] showed that treatment with Pg increased all the antioxidant enzymes such as SOD. Also, Kong et al. [58] reported that Pg increases Cu/Zn-SOD expression in rats and reduces oxidative stress by increasing SOD activity. Our study also showed that oral administration of Pg to arthritic rats induced a significant increase in blood GSH level. These results are in agreement with the findings of Shahin et al. [49], who reported similar results.

Combinations used in this study

MTX is also used widely in combination with other medications, most notably biotherapies, to increase their therapeutic effect [59]. In the present study, we examined the administration of two different combinations between MTX and drugs under investigations. The three combinations were (a) MTX + PTX and (b) MTX + Pg. The two combinations were administered to both CFA and PIA animals, to yield a final number of four combinations. All these combinations could treat the pathological changes caused by arthritis. Our results showed that the administration of the two combinations between MTX and drugs under investigation (MTX + PTX) (MTX + Pg), after induction of RA, all elicited a significant decrease in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level and blood SOD level, and a significant increase in the blood GSH level. On comparing all combinations, the combination of Pg with MTX was found to be the most potent one. It led to a higher significant decrease in the arthritic index, ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level, and a higher significant increase in blood GSH level. Finally, the least potent combination was PTX with MTX.

However, when comparing each drug alone with its combination, the following was observed:

  1. Treatment with the (MTX+PTX) combination showed marked improvement than PTX alone. These results are in agreement with the findings of Rinella et al. [60], who reported similar results. Hisadome et al. [61] reported that anti-TNF-a in combination with MTX markedly decreases joint destruction in RA.
  2. The combination of MTX + Pg was more effective than MTX and Pg each alone. The concomitant use of the PPAR-g agonist, Pg, and MTX appears to be a promising therapeutic strategy for RA patients. The Shahin et al. [49] study was consistent with our opinion.



  Conclusion Top


Pristane proved to be slightly better than CFA in induction of RA. Also, PIA produces a model that has chronicity resembling human RA. Each model of induction, either CFA or pristane, proved the efficacy of MTX as being the cornerstone of disease-modifying treatment in patients with RA. Our study showed that both the drugs, PTX and Pg, showed anti-inflammatory properties and strong antioxidant activities when administered as treatment to arthritic rats each alone or in combination with MTX. The anti-inflammatory properties of these drugs were confirmed by a reduction of ESR, serum RF level, serum CRP level, serum TNF-a level, serum nitrite level, and blood SOD level, whereas who reported antioxidant activities of these drugs were confirmed by an increase in the blood GSH level. When comparing the two drugs alone, it was found that Pg was the most potent drug in treating arthritic rats, followed by PTX with lesser potency. Our study showed that Pg alone plays a promising role in the treatment of RA. However, it was more active in combination with MTX than each alone. The present investigations also suggested that these drug combinations with MTX can play a promising role in the treatment of RA. However, on comparing all combinations, the combination of Pg with MTX was the most potent. Finally, the least potent was the combination of PTX with MTX. In addition, when a comparison between the combinations and each drug alone was carried out, it was found that all combinations showed more efficacy and potency than each dug alone.


  Acknowledgements Top


Conflicts of interest

There are no conflicts of interest.

 
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