Abstract: Objective: To explore the protective effects of hydrogen sulfide (H₂S) on kidneys of type 1 diabetic rats and its underlying mechanism. Methods: Thirty-two male SD rats were randomly divided into four groups:normal control (NC) group, diabetes mellitus (DM) group, DM treatment (NaHS+DM) group and NaHS control (NaHS) group. The rats from DM group and NaHS+DM group were injected intraperitoneally with Streptozotocin 55 mg/kg to induce type 1 diabetes mellitus (n=8). After modeling, rats in NaHS+DM group and NaHS group were intraperitoneally injected with NaHS solution at the dosage of 56 μmol/kg. After 8 weeks, urinary protein content was detected in urine samples collected for 24 h. and the ratio of kidney weight/body weight (renal index) was determined in isolated kidneys. Besides, the levels of fasting blood glucose (FBG), blood urea nitrogen (BUN) and serum creatinine (Scr) were measured biochemically. The morphological changes of renal tissue were observed by HE staining. The content of malondialdehyde (MDA), the activities of superoxide dismutase (SOD) and Caspase-3 in renal tissue were determined by spectrophotometry. The protein expression levels of Bcl-2 and Bax in renal tissue were detected using Western blot. Results: There was no significant difference in the respective measured indexes in rats between NC group and NaHS group. However, in DM group, the levels of 24 h urinary protein, FBG, BUN, Scr and renal index were increased significantly; HE staining showed that the basement membrane was thickened and the amount of glomerular mesangial matrix was increased; MDA content, Caspase-3 activity and Bax expression levels were increased, while SOD activity and Bcl-2 expression were decreased. Compared with those in DM group, the morphological changes of renal tissue and its function were improved; MDA content, Caspase-3 activity and Bax expression were decreased significantly, while SOD activity and Bcl-2 expression were increased obviously in NaHS+DM group. Conclusion: H₂S can protect the kidneys of type 1 diabetic rats, which is related to suppressing oxidative stress and cell apoptosis.

Key words: hydrogen sulfide, diabetes mellitus, rat, renal function, oxidative stress, cell apoptosis