Abstract: Objective To explore the effects of hydrogen sulfide (H2S) on myocardial fibrosis and expressions of MAPK1/3 and
MMP-8 in diabetic rats. Methods Forty adult male SD rats were randomized into 4 groups, namely the control group, diabetes
mellitus group (STZ group), diabetes mellitus with H2S treatment group (STZ+H2S group), and normal rats with H2S treatment
group (H2S group). Diabetes was induced by intraperitoneal injections of 40 mg/kg streptozotocin (STZ). The rats in the control
group received daily intraperitoneal injections of saline, and those in STZ+H2S group and H2S group were given NaHS (100
μmol/kg) injections. After 8 weeks, the pathologies of cardiac fibrosis were examined with HE staining, and the expressions of
collagen I, MAPK1/3 and MMP-8 were analyzed with Western blotting. Results Compared with the control group, the diabetic
rats showed increased collagen content and obvious interstitial fibrosis in the myocardial tissue with significantly increased
expression levels of collagen I, MAPK1/3 and MMP-8 (P<0.05); all these changes were obviously reversed by treatment with
H2S (P<0.05). Collagen I, MAPK1/3 and MMP-8 expression levels and the degree of myocardial fibrosis were comparable
between H2S group and control group (P>0.05). Conclusion Hydrogen sulfide can attenuate cardiac fibrosis in diabetic rats,
and the mechanism may involve the inhibition of MAPK1/3/MMP-8 signal pathway.