Establishment Of The Rheumatoid Arthritis Model In Rats And The Role Of Plasma Kallikrein In Rheumatoid Arthritis

Part1Establishment and evaluation of rat model of rheumatoid arthritisObjective A rat model of rheumatoid arthritis was established and itspathogenesis were further studied in order to set foundation for subsequent work ondeveloping new effective therapeutic measures on this disease.Methods20female Lewis rats aging6-8weeks, were randomly divided into2groups：control group(n=8), model group(n=12). Rats with arthritis were induced by beinginjected with Freund’s complete adjuvant containing bovine type II collagensubcutaneously in the proximal quarter of the tail. During the experimental period，thegeneral conditions of two groups were observed, body weight and ankle diameter wererecorded. The arthritis index of experimental rats were graded in weeks1、2、3、4after theinitial immunization according to an established scoring system. X-ray photos were takenin weeks0、4、12and MR（Imagnetic resonance imaging）exam were performed in weeks0、2、3、4after the initial immunization. HE staining of bone tissue were performedaccording to the standard procedure to determine the extent of arthritis in weeks2、3、4、12after the initial immunization. Blood sampling in rat eyes were assayed for the level ofTNF-α and IL-1β by ELISA in weeks3and cytokines by Rat Cytokine Array Panel ArrayKit on days11after the initial immunization.Results Rats in the control group growed fast and there were no sign of erythemaon ankle joint. On the other hand, rats in the model group experienced slow growth. Theankle joint swelling of the model group began to be present on the day12and reached thepeak on day21after the initial immunization, Arthritis scores raised significantlycomparing to rat in the control group. X-ray results, MRI and histopathologicalexamination of the synovial tissue, cartilage and bone tissue of the model rats showed typical arthritis disease. ELISA tests shown TNF-αand IL-1β level of model group weremuch higher than control group with p<0.05. Cytokine analysis showed that a variety ofchemokines expression increased in model rats serum.Conclusion1. RA rat model can be readily and effectively induced using injectionof bovine collagen type II emulsified with complete Freund’s adjuvant. It also revealed thatthis metod can cause a high morbidity rate among lewis rat.2. Collagen-induced arthritis(CIA) rat model have great similarity with human RA in clinical feature and pathologiccharacteristics. Therefore, this model can set foundation for further research into themechanism of human RA and the development of new antirheumatic drugs. Part2The role of plasma kallikrein in the collagen-induced arthritis ratsObjective To explore the effects and mechanism of plasma kallikrein incollagen-induced arthritis rats.Methods Establish collagen-induced arthritis (CIA) model as stated in part1andmeanwhile, part of the experimental group were treated using the following plasmakallikrein inhibitor: EPI-KAL-2and13G11. Arthritis Scores in rats are visually examinedfor signs of joint inflammation during the experiment and arthritis scores are obtained inweek1、2、3、4after the initial immunization. TNF-a、IL-1β level and complement factorsC3a and C5a in eye blood serum are tested using ELISA method in week4after the initialimmunization.Results Rats in the control group growed fast and there was no swelling on anklejoint. On the other hand, Rats in the model group experienced slow growth, Swelling of theankle joint were also discovered. Compared to the rats in the model group, the jointswelling degree and arthritis scores of EPI-KAL-2、13G11-treated CIA model group weresignificantly reduced. There was no statistical significance of the levels of TNF-α andIL-1β between13G11-treated CIA model group and PBS-treated CIA model group, buthigher than the control group. Meanwhile, there was no statistical significance of the levelsof C3a in the control group,13G11-treated CIA group and PBS-treated CIA model group.The level of C5a in13G11-treated CIA model group was no different from the control group but significantly lower than PBS-treated CIA model group.Conclusion1.The plasma kallikrein inhibitor EPI-KAL-2and13G11can obviouslyreduce the degree of inflammation in CIA rats.2. The kallikrein inhibitor may reduce thedegree of inflammation via lowing the level of complement factor C5a.3.The plasmakallikrein inhibitor may be used as an effective drug treating rheumatoid arthritis.