Toxicity Study Of Qinqi Oral Liquid And Therapeutic Effect On Myocardial Inflammation Induced By EMCV

Objective: To investigate the acute and chronic toxicity as well as to evaluate the safety level of Qinqi?oral liquid?,and to investigate the immunoregulatory and protective effect of Qinqi on Viral myocarditis?VMC?in mice.Methods: 1.Acute toxicity test: The acute toxicity of Qinqi oral liquid was determined by the maximum dose,and the safety was evaluated.2.Long-term toxicity test: 80 SD rats were randomly divided into low,medium and high dose groups of Qinqi oral liquid and blank control group,20 rats in each group,half male and half female,and administered continuously for 30 days.After 24 h and 15 d of cessation of administration,necropsy,blood biochemical examination and pathological tissue section observation were performed.3.Establishment of VMC model: The myocardial pathological changes at different time points were observed at 3,7,10,and 14 days after challenge.The mRNA and EMCV load of myocardial IL-1?,IL-6 and TNF-? were detected by q PCR,and the levels of IL-1?,IL-6 and TNF-? were detected by ELISA.4.Pharmacodynamics test: 180 male Kunming mice were randomly divided into control group and model group,low-,medium-,and high-dose groups of Qinqi oral liquid,and ribavirin-positive control group.The model group and each treatment group were intraperitoneally injected with 0.2 mL of culture medium containing 10⁶ TCID₅₀ EMCV,and the control group was injected with 0.2 mL of culture solution.After 24 hours of challenge,the mice in the low,middle and high doses of Qinqi oral liquid were intragastrically administered with 0.1 mL of 0.6,1.2,2.4 g · mL^-1 sputum oral solution for 6 days,and the positive control group was intraperitoneally injected with 0.1.mL ribavirin 6 d;the control group and the model group were given distilled water for 6 days.On the third day of the experiment,8 mice were sacrificed in each group.On the 7^th day,the surviving mice of each group were weighed and sacrificed,and the heart was fixed and frozen.The cardiac tissues were pathologically integrated.The expressions of myocardial EMCV,IL-6,IL-23 A,IL-17 A and TGF-? mRNA were detected by q PCR.The ratio of Th17 cells to Treg cells in spleen was detected by flow cytometry.Results:1.The maximum dose of Qinqi oral solution in the acute toxicity test is equivalent to 540 times the clinical daily dose of pigs.In the long-term toxicity test,compared with the blank control group,there were no significant differences in appearance signs,behavioral activities,body weight gain,hematology and blood biochemical parameters between the groups?P>0.05?;There is no systemic necropsy and organs pathological changes occurred.No delayed drug toxicity was observed after discontinuation of the drug.2.EMCV-infected mice can cause myocardial injury and inflammation in mice,inflammatory factors began to increase on the 3^rd day,reached the peak on the 7^th day.3.pharmacodynamics test: Th17 and Treg cells in spleen and the EMCV 3D viral load as well as the expression of IL-6,IL-23 A,IL-17 A and TGF-? mRNA were analyzed in the myocardium.Qinqi significantly reduced the clinical severity of myocarditis and the overall mortality rate as well as the expression of IL-6,IL-23 A,IL-17 A mRNA and EMCV 3D viral load in the myocardial microenvironment on the 7^th day.The Qinqi high dose on day 3^rd and middle dose on day 7^th significantly increased the expression of TGF-? mRNA;moreover,the middle and high doses on the 7^th day significantly reduced the ratio of Th17/Treg cells in spleen.Conclusion: Qinqi regulated the effect of Th17/Treg homeostasis in the microenvironment of the body and myocardial tissue caused by EMCV-induced viral myocarditis,and reduced myocardial damage caused by viral inflammation.Conclusions:1.Qinqi oral liquid is safe and non-toxic to large mice,which provides a basis for clinical trials of target animals.2.Qinqi oral solution can reduce myocardial damage caused by viruses and inflammation,and regulate the homeostasis of the body Th17/Treg.