| Background: Osteoarthritis(OA)is a chronic degenerative disease characterized by joint pain and limited function.With the development of aging society,the incidence rate is increasing year by year,and the disability rate is high.It has been reported that in 2017,about 303 million people worldwide suffered from osteoarthritis.There is currently no drug that can effectively prevent the continued progress and destruction of the joints of patients with OA.In the later stages,patients can only improve their quality of life through joint replacement.Articular cartilage has limited ability to repair itself after injury.In recent years,studies have found that mesenchymal stem cells(MSC)can promote cartilage repair.Many animal studies and clinical RCT studies have confirmed the effectiveness of MSC in the treatment of OA.Alleviate the symptoms and signs of arthritis,improve joint function,but there is no histopathological evidence that cartilage structure is significantly improved.Progressive cartilage degeneration is the key to the onset of OA,and is driven by the catabolism of cartilage matrix and anti-chondrocyte anabolism.MSC can promote the synthesis of articular cartilage and secrete a variety of nutritional factors(TGF,IGF)to inhibit chondrocyte apoptosis to repair cartilage defects,but it has a limited role in cartilage catabolism mediated by inflammatory factors.Therefore,the treatment of OA only by promoting the synthesis of articular cartilage is inadequate and can not interrupt the pathological process of cartilage degeneration progress.Studies have confirmed that different inflammatory environments can promote the remodeling of the immune phenotype of MSCs and become two forms of pro-inflammatory MSC-1 or anti-inflammatory MSC-2.Studies have reported that high-concentration IL-17 pre-treated MSC(MSC-17)not only has the ability to differentiate into cartilage,bone,and fat as untreated MSC(UT-MSC);and the immunosuppression and anti-inflammatory of MSC after pretreatment is strengthened.Therefore,we speculate that the anti-inflammatory MSC-17 not only has the effect of promoting cartilage synthesis,but also has a better effect on inhibiting inflammatory factors and delaying cartilage catabolism than UT-MSC,and is expected to become a new effective treatment method for OA.Purpose:To explore the therapeutic effect and mechanism of IL-17 pretreated dental pulp mesenchymal stem cells in papain induced OA model in rats.Method:1.Immunologic function of IL-17 induced of anti-inflammatory Dental pulp mesenchymal stem cells(DPMSC)DPMSCs were pretreated with IL-17 at different concentrations for 120 h to observe the morphology of DPMSC.DPMSC induced by IL-17 and UT-DPMSC were isolation co-cultured with T lymphocytes for 120 h,respectively,and T lymphocyte proliferation was detected at 24 h,48h and 120 h.At 120 h,supernatant was collected to detect cytokines.2.The effect of anti-inflammatory DPMSC on OA rat34 healthy 12-week-old female SD rats were selected and injected with 4% papain in the joint cavity for building osteoarthritis rat model.Synovial membrane and cartilage primary cells were isolated and cultured from the two OA model rats,and then synoviocytes and chondrocytes were isolation co-culture with high DPMSC-17 and UT-DPMSC,respectively,to detect cell proliferation and supernatant cytokines.The remaining 32 model rats were randomly divided into four groups,group A: normal saline group;group B: sodium hyaluronate group;group C: UT-DPMSC group;group D: high DPMSC-17 group;using joint cavity injection,Once a week,continuous treatment for 4 weeks,observe the changes of the rat knee joint.After the rats were sacrificed,joint synovial fluid was taken to measure the content of IL-1? and TNF-?;knee joints were taken for HE staining and OARSI score.Result:1.Immunologic function of IL-17 induced of anti-inflammatory DPMSC(1)The morphology and size of DPMSC-17 and UT-DPMSC did not change significantly.(2)T lymphocyte proliferation in the four groups treated with UT-DPMSC,low,medium,and high DPMSC-17 was significantly lower than that the T lymphocyte control group(P<0.05);and the degree of T lymphocyte proliferation in the high DPMSC-17 treatment group was lower than the UT-DPMSC treatment group(P <0.05).(3)Cytokines in the supernatant:(1)compare with the T lymphocyte control group,the levels of IL-6 and TNF-? in the three groups treated with UT-DPMSC,medium DPMC-17,and high DPMSC-17 were significantly reduced,but low DPSMC-17 increased(P<0.05),and the high DPMSC-17 group was lower than the UT-DPMSC group(P<0.01);IL-4 levels increased significantly in the two groups treated with medium and high DPMSC-17,and the opposite in the low DPMSC-17 group(P<0.01).2.The effect of anti-inflammatory of DPMSC on OA rat(1)Color Doppler ultrasound inspection:Group A: joint swelling and fluid accumulation was obvious,blood flow signal and osteophyte formation were visible.Group B: joint swelling was obvious,and fluid accumulation increased,osteophyte formation and a small amount of blood flow signal were seen.Group C: The joints were slightly swollen and a small amount of fluid was formed.A small amount of hypoechoic was seen on the joint surface,and no obvious blood flow signal was seen.Group D: There was no swelling of the joints,and no obvious fluid accumulation and blood flow signals were seen.(2)Proliferation and cytokines of synoviocytes and chondrocytes:(1)Compared with the synoviocytes control group,synoviocytes proliferation in the UT-DPMSC and high DPMSC-17 treatment groups was significantly lower than that in the synoviocytes control group(P<0.05);The levels of IL-1?,IL-6 and TNF-?were significantly reduced in the UT-DPMSC and high DPMSC-17 treatment groups,and the content of the high DPMSC-17 group was the lowest,the difference was statistically significant(P<0.05).(2)Compared with the chondrocyte control group,chondrocyte proliferation of the UT-DPMSC and high DPMSC-17 treatment groups was significantly higher than that of the chondrocyte control group(P<0.05),and the proliferation of the high DPMSC-17 group was higher than that of the UT-DPMSC group;The levels of IL-1?,IL-6 and TNF-? were significantly reduced in the UT-DPSMC and high DPMSC-17 treatment groups,and the content of the high DPMSC-17 group was the lowest(P<0.05).(3)HE score: Group A: calcified cartilage collapsed and fragmented seriously,cartilage severely degenerated,synovial tissue hyperplasia and giant osteophyte formation;Group B: calcified cartilage collapsed and severely fragmented,cartilage was significantly degraded,synovial tissue hyperplasia and large Osteophyte formation;Group C: moderate degeneration of articular cartilage,hyperplasia of synovial tissue,incomplete tidal line,multiple obvious fractured areas,articular cartilage is not collapsed into the epiphysis;Group D: articular cartilage degenerates slightly,with small osteophytes Formation,calcified cartilage has a slight local fragmentation.According to the OARSI score analysis: compared with the sodium hyaluronate group,the OARSI score of the UT-DPMSC and high DPMSC-17 groups were significantly reduced(P<0.05),and the high DPMSC-17 group was lower than the UT-DPMSC.(4)Cytokines of joint synovial fluid: Compared with the sodium hyaluronate group,the levels of TNF-? and IL-? in UT-DPMSC and high DPMSC-17 groups decreased significantly,and the high DPMSC-17 group showed the most significant decrease.It is statistically significant(P<0.05).Conclusion:(1)Compared with UT-DPMSC,IL-17 pretreated DPMSC had no obvious change in morphology and size;high DPMSC-17 had stronger inhibitory effect on T lymphocyte proliferation and proinflammatory factor secretion than UT-DPMSC.(2)Compared with UT-DPMSC,high DPMSC-17 has enhanced the effect of inhibiting synovial and chondrocyte secretion of pro-inflammatory factors such as IL-1,IL-6,TNF-?,and chondrocyte synthesis,while reducing joint destruction,improving the OARSI of HE staining and reducing intra-articular inflammation level in OA model rats,and it is better than that of UT-DPMSC. |
PDF Full Text Request