Therapeutic Effect Of Small Interfering RNA Vector Of Peptidyl Arginine Deiminase 4 On Collagen-induced Arthritis In Mice

Objective To study the therapeutic effect and mechanism of small interfering RNA vector of Peptidyl arginine deaminase 4 on collagen-induced arthritis mice.Method CIA model was established using bovine type II collagen.The experiment was divided into blank group(DBA/I mice did not do any treatment),model group(no other treatment after CIA mice were established),negative control group(established CIA mice injected empty)The virus solution prepared by the vector),the PAD4-siRNA1 group(the virus solution prepared by injecting the PAD4-siRNA1 vector after the CIA mouse was established),the PAD4-siRNA2 group(the virus solution prepared by injecting the PAD4-siRNA2 vector after the CIA mouse was established)and In the PAD4-siRNA3group(the virus solution prepared by injecting the PAD4-siRNA3 vector after CIA mice),4 mice in each group were given a tail vein injection once a week,8 times a week.At the end of the experiment,the mice were sacrificed.The expression of PAD4 m RNA in joints was detected by RT-PCR.The expression of PAD4 protein in joints was detected by fluorescence immunohistochemistry.The helper cells in spleen cells and thymocytes were detected by flow cytometry.TH17 and Treg changes;HE staining to observe the pathological changes of mouse joints.Results(1)Compared with the blank group,the expression level of PAD4 m RNA in the bone tissue of the model group was significantly increased(P<0.05).After PAD4-siRNA treatment,the expression level of PAD4 m RNA was significantly lower than that of the model group and the negative control group.(P<0.05).(2)PAD4 protein was rarely expressed in the joints of the blank group,but PAD4 expression was observed in the bone destruction area of the model group,and the protein expression was decreased after PAD4-siRNA treatment.(3)Compared with the blank group,the ratio of Th17 and Treg cells and the ratio of Th17/Treg in the spleen of the model group and the negative control group were increased(P<0.05).Compared with the model group and the negative control group,the ratio of Th17 cells in the PAD4-siRNA1 group and The ratio of Th17/Treg was decreased(P<0.05).The proportion of Th17 cells in the other two groups was increased(P<0.05),and the ratio of Th17/Treg was not obvious.The proportion of Treg cells in PAD4-siRNA1 group decreased,and the proportion of Treg cells in the other two groups.Elevated,but only PAD4-siRNA3 group was statistically significant(P<0.05).(4)Compared with the blank group,the proportion of Th17 cells in the thymus of the model group and the negative control group was increased(P<0.05),the proportion of Treg cells was decreased(P<0.05),and the ratio of Th17/Treg was increased(P<0.05).PAD4-siRNA After treatment,the proportion of Th17 cells decreased,the proportion of Treg cells increased,and the ratio of Th17/Treg decreased.However,only the PAD4-siRNA2 group was statistically significant for Th17 cells(P<0.05),and only the PAD4-siRNA1 group for Treg cells.Statistical significance(P<0.05),for the Th17/Treg ratio,the three groups were statistically significant(P<0.05).(5)The articular surface of the mice in the blank group was smooth,bone erosion and destruction occurred in the joints of CIA mice,and the degree of joint destruction of CIA mice was reduced after the action of PAD4-siRNA.Conclusions Gene silencing of PAD4 expression can reduce the joint score of CIA mice,reduce Th17,increase Treg,reverse Th17/Treg imbalance,and improve the pathological changes of joints,thus having a certain therapeutic effect on CIA mice.