Effect Of Low Dose IL-2 On Mitochondrial Function Of NOD Mouse Treg Cells In Sjogren’s Syndrome Model

Objective:To observe the therapeutic effect of low-dose IL-2 on model mice with Sjogren’s syndrome,and to explore the effect of mitochondrial changes on the function of Treg cells in NOD mice treated with low-dose IL-2.Methods:1.Experimental animals:NOD/Shi Lt J mice were randomly divided into three groups:disease control group,low-dose IL-2 treatment group and saline treatment group.Mice in the control group received no treatment,mice in the low-dose IL-2treatment group received intraperitoneal injection of IL-2 at 30,000 IU/day,and mice in the saline treatment group received intraperitoneal injection of normal saline at the same volume for a total of 8 weeks.2.Observation indicators:The saliva flow rate of mice was detected every 2weeks,and the mice were sacrificed 8 weeks later.The submandibular glands of mice were collected and the lymphocyte infiltration was evaluated by HE staining method.The peripheral blood of mice was collected and the serum anti-SSA/SSB antibodies were determined by Elisa method.Mitochondria and ROS of Treg cells were detected by immunofluorescence.Results:1.Saliva flow test results of NOD miceOn day 0,there was no significant difference in saliva flow among the three groups（p>0.05）.On day 14,28 and 42,there was no significant difference in saliva flow between the disease control group and the saline treatment group（p>0.05）,the saliva flow in low-dose IL-2 treatment group was significantly higher than that in disease control group and saline treatment group（p<0.01）.2.HE staining results of submandibular gland in NOD miceThere was no significant difference between the control group and the saline group（p>0.05）,and compared with the disease control group and saline treatment group,the area ratio of lymphatic lesion infiltration in the submandibular gland was significantly decreased in the low-dose IL-2 treatment group（p<0.05）;There was no significant difference in the density of submandibular gland lymph foci between the control group and the saline group（p>0.05）,and compared with disease control group and saline treatment group,the density of lymphatic focus in submandibular gland was significantly decreased in low-dose IL-2 treatment group（p<0.05）.3.Detection of serum anti-SSA/SSB antibody in NOD miceThere was no significant difference in OD values of serum anti-SSA/SSB antibody between control group and saline treatment group（p>0.05）,the OD value of serum anti-SSA/SSB antibody in low-dose IL-2 treatment group was significantly decreased compared with disease control group and saline treatment group（p<0.01）.4.Flow cytometry of NOD mouse Treg cellsThere was no significant difference in the proportion of CD25+CD127^lowTreg cells in CD4⁺CD45RA^-T cells between the control group and the saline group（p>0.05）,no significant difference was found in MG proportion in CD25⁺CD127^low/-Treg cells（p>0.05）.The proportion of CD25⁺CD127^low/-Treg cells in low-dose IL-2 treatment group was significantly higher than that in disease control group and saline treatment group（p<0.05）and the MG proportion in CD25⁺CD127^low/-Treg cells was significantly higher than that in disease control group and saline treatment group（p<0.05）.5.Immunofluorescence test of NOD mouse Treg cellsThere was no significant difference in the mean MG fluorescence intensity between the disease control group and the low-dose IL-2 treatment group,and the mean MG fluorescence intensity in the low-dose IL-2 treatment group was significantly higher than that in the saline treatment group（p<0.05）;There was no significant difference between JC-1 monomer and mt ROS in disease control group and saline treatment group（p>0.05）,and JC-1 monomer and mt ROS in low-dose IL-2 treatment group were significantly lower than those in disease control group and saline treatment group（p<0.05）.Conclusion:1.Low-dose IL-2 treatment can significantly improve salivary gland and submandibular gland injury and improve the condition of NOD dry mice.2.Low dose of IL-2 can affect the function of Treg cells by regulating their mitochondria.