Abstract: Objective To explore the effect of heme oxygenase-1 (HO-1) on endothelial function and kidney injury in diabetic nephropathy. Methods Rats were divided into control, diabetes mellitus (DM) , Hemin (HO-1 inducer) and ZnPP (HO-1 inhibitor) groups. All samples were collected on 5w, 10w and 15w. Expression of HO-1 in renal tissue were examined by IHC and RT-PCR, malondialdehyde (MDA) contents, superoxide dismutase(SOD) activity, levels of NO product and iNOS，eNOS in renal tissue were detected. Urinary albumin excretion rate (UAER) was also observed. Results The content of MDA was progressively increased in kidney of DM rats. Up regulated HO-1 mRNA expression in renal tissue detected by RT-PCR and significantly enhanced of HO-1 expression detected by IHC from DM rats were observed when compared with those of control group. iNOS was decreased and eNOS was increased in DM rats. After pretreatment with Hemin for 5 weeks in DM rats, MDA and UAER were lower than that of DM 5w group. Alternatively, pretreatment with ZnPP in DM rats, a higher content of MDA, and UAER were measured. While eNOS was reduced after treatment with Hemin, NO product was obviously heightened following eNOS induced after administration Znpp. Conclusions Up regulation of HO-1 may ameliorate the renal injury in diabetic nephropathy.

Key words: endothelial function, Heme oxygenase-1, Diabetes mellitus rat, renal injury