Abstract: AIM: To investigate the changes of aldehyde dehydrogenase 2 (ALDH2) on myocardial injury in different stages of diabetic rats and analyze the related mechanism. METHODS: Diabetic (DM) model in SD rat was induced by a single intraperitoneal injection of 55 mg/kg streptozoticin (STZ). DM rats were divided into fourth week (DM4W), eighth week (DM8W) and twelfth week (DM12W) groups. The ventricular hemodynamic parameters were recorded, plasma interleukin-1 (IL-1), interleukin-4 (IL-4) and cardiac 4-hydroxynon-2-enal (4-HNE) levels were determined by enzyme-linked immuno sorbent assay (ELISA), cardiac ALDH2 activity was measured. The expressions of Bax and Bcl-2 at mRNA level of left anterior myocardium were detected by RT-PCR. RESULTS: In contrast to control group, in DM4W, DM8W and DM12W groups, left ventricular development pressure (LVDP), heart rate (HR) and left ventricular work (RPP) were decreased(P<0.01), plasma IL-1 level was increased while IL-4 level was decreased(P<0.01). Cardiac 4-HNE level was increased, and ALDH2 activity was decreased(P<0.01). The expression of Bax mRNA level was increased(P<0.01), Bcl-2 mRNA level was decreased(P<0.01) and Bcl-2/Bax mRNA were decreased(P<0.01). And with the development of diabetic progression, LVDP, HR, RPP, IL-4, ALDH2 activity and Bcl-2/Bax mRNA were further reduced(P<0.05 or P<0.01). 4-HNE and IL-1 levels were increased(P<0.05 or P<0.01). CONCLUSION: With the development of diabetes, cardiac ALDH2 activity was further decreased, which may be related to the increase of inflammatory injury and the happening of apoptosis.

Key words: diabetes, aldehyde dehydrogenase 2, 4-hydroxynon-2-enal, inflammatory injury, apoptosis