[Effect of hydrogen sulfide on inducible nitric oxide synthase in kidneys of Type 1 diabetic rats].

OBJECTIVE: To investigate effects of hydrogen sulfide (H2S) on inducible nitric oxide synthase (iNOS) in kidneys of Type 1 diabetic rats.
 Methods: Thirty-two male SD rats were randomly divided into four groups: A normal control (NC) group, a diabetes mellitus (DM) group, a NaHS (NaHS+DM) group, and a NaHS control (NaHS) group (n=8 per group). Type 1 diabetes was induced by a single intraperitoneal injection of streptozotocin (55 mg/kg). After successful establishment of models, the rats in NaHS+DM and NaHS groups were injected with NaHS solution (56 μmol/kg) intraperitoneally. Eight weeks later, the activities of total nitric oxide synthase (T-NOS) and iNOS, as well as the level of nitric oxide (NO) were detected in serum and renal tissues, respectively. The activity of glutathione peroxidase (GSH-Px) was determined in renal tissues. The ultrastructures of renal tissues were observed by transmission electron microscope. The protein expression of iNOS in renal tissues was detected by Western blot.
 Results: Compared with the NC group, there was no significant difference in the various indexes in the NaHS group (P>0.05). However, in the DM group, the activities of T-NOS and iNOS, and the level of NO were all increased significantly in serum and renal tissues, while the activity of GSH-Px was decreased in renal tissues. Under the electronic microscope, the thickening of the glomerular capillary basement membrane, the proliferation of mesangial matrix, and the foot fusion were observed. The protein expression of iNOS was increased obviously in renal tissues in the DM group (P<0.01). Compared with the DM group, the activities of T-NOS and iNOS and the level of NO were all decreased in serum and renal tissues, while the activity of GSH-Px was increased in renal tissues in the NaHS+DM group (P<0.01). The renal ultrastructural damages were ameliorated obviously. The protein expression of iNOS was decreased significantly (P<0.01).
 Conclusion: H2S exerts a protective effect on kidney injury in type 1 diabetic rats. The mechanism might be related to inhibition of iNOS activity and protein expression, in turn leading to reduction of NO content in renal tissues.