Abstract: Objective To explore the effects of hemeoxygenase-1 (HO-1) induction on matrix metalloproteinase 2 (MMP-2) and MMP-9 expression in liver of spontaneously hypertensive rats (SHR). Methods Rats were randomly divided into 4 groups. Wistar induction group (WH) and SHR induction group (SH): 8 g/L hemin was administered to the animals intraperitoneally at a concentration of 15 mg/kg/d for 4 consecutive days to induce expression of HO-1; Wistar control group (W) and SHR control group (S): equal volume of 0.1 mol/L NaOH (pH 8.3) was administered intraperitoneally as controls. Systolic blood pressure (BP) of rats was determined. The expressions of HO-1, MMP-2 and MMP-9 in liver were determined by immunohistochemistry. The relative activity of MMP-2 and MMP-9 in plasma were detected by gelatin zymography. Results The expressions of liver HO-1, MMP-2 and MMP-9 were significantly higher in WH and SH group compared with W and S group, respectively (p<0.01). Induction of HO-1 significantly attenuated BP of SHR. The relative activity of MMP-2 and MMP-9 in rat plasma was significantly higher in S group compared with W group (p<0.01). The relative activity of MMP-2 and MMP-9 in rat plasma was significantly higher in WH and SH group compared with W and S group, respectively (p<0.01). Conclusions HO-1 up-regulates expressions of MMP-2 and MMP-9 in liver of SHR and the mechanisms need to be further elucidated.

Key words: hemeoxygenase-1, matrix metalloproteinase, hypertension