Abstract: Abstract:Objective  To explore the effect of  Soybean saponins(SS)  on the expressions of  NOX4 and p22phox in the myocardium tissues of diabetic rats,and to clarify its protective effect on myocardium.Methods Male Wistar rat models of diabetes mellitus were randomly divided into diabetes  group and SS treatment group,the rats in two groups were given daily saline and SS(10 mg/Kg)orally for 3 months;the rats treated with 0.1 mol/L citrate buffer were used as control group and administrated with saline for 3 months;then the animals were killed and the  myocardium tissues were obtained.The NOX4 and p22phox mRNA expressions in rat myocardium tissues were detected with real-time fluorescence quantitative polymerase chain reaction (PCR).Immunohistochemistry was used to detect the expressions of copper-zinc superoxide dismutase (Cu-Zn-SOD) and connective tissue growth factor(CTGF) in myocardium tissues.HE staining was performed to observe the pathological changes of myocardium.Results  Compared with control group,the expression levels of NOX4 mRNA,p22phox mRNA and CTGF protein in myocardium tissues of rats in diabetes  group were significantly increased(P<0.01),and the Cu-Zn-SOD protein expression level was significantly decreased(P<0.01).Compared with diabetes  group,the expression levels of NOX4 mRNA,p22phox mRNA and CTGF protein in myocardium tissues of rats in SS treatment group were significantly reduced(P<0.01),but the Cu-Zn-SOD protein expression level was significantly increased(P<0.01);there was no significant difference of the indexes mentioned above between control group and SS treatment group (P>0.05).HE staining showed the rat myocardial cells in  control group were tightly and neatly packed,but the rat myocardial cells in diabetes  group arranged loosely and disorderly with infiltration of inflammatory cells in mesenchyma,and the myocardial cells in SS treatment group were also tightly and neatly packed.Conclusion SS can reduce the expression levels of NOX4 mRNA,p22phox mRNA and CTGF protein  in myocardium tissues of diabetic rats,increase the expression level of Cu-Zn-SOD protein and alleviate myocardial damage induced by  oxidative stress,which has a protective effect on the myocardium.

Key words: Soybean saponin, diabetes mellitus, copper-zinc superoxide dismutase, NADPH oxidase, connective tissue growth factor, rats,Wistar