Protection of Veratrum nigrum L. var. ussuriense Nakai alkaloids against ischemia-reperfusion injury of the rat liver.

OBJECTIVE

To investigate the protective effects and possible mechanisms of Veratrum nigrum L.var. ussuriense Nakai alkaloids (VnA) on hepatic ischemia/reperfusion (I/R) injury in rats.

METHODS

Forty male Wistar rats were randomly divided into four experimental groups (n = 10 in each): (A) Control group (the sham operation group); (B) I/R group (pretreated with normal saline); (C) Small-dose (10 microg/kg) VnA pretreatment group; (D) Large-dose (20 microg/kg) VnA pretreatment group. Hepatic ischemia/reperfusion (Hepatic I/R) was induced by occlusion of the portal vein and the hepatic artery for 90 min, followed by reperfusion for 240 min. The pretreatment groups were administered with VnA intraperitoneally, 30 min before surgery, while the control group and I/R group were given equal volumes of normal saline. Superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity and nitric oxide (NO) content in the liver tissue at the end of reperfusion were determined and liver function was measured. The expression of intercellular adhesion molecule-1 (ICAM-1) and E-selectin (ES) were detected by immunohistochemical examinations and Western blot analyses.

RESULTS

The results showed that hepatic I/R elicited a significant increase in the plasma levels of alanine aminotransferase (ALT: 74.53 +/- 2.58 IU/L vs 1512.54 +/- 200.76 IU/L, P < 0.01) and lactic dehydrogenase (LDH: 473.48 +/- 52.17 IU/L vs 5821.53 +/- 163.69 IU/L, P < 0.01), as well as the levels of MPO (1.97 +/- 0.11 U/g vs 2.57 +/- 0.13 U/g, P < 0.01) and NO (69.37 +/- 1.52 micromol/g protein vs 78.39 +/- 2.28 micromol/g protein, P < 0.01) in the liver tissue, all of which were reduced by pretreatment with VnA, respectively (ALT: 1512.54 +/- 200.76 IU/L vs 977.93 +/- 89.62 IU/L, 909.81 +/- 132.76 IU/L, P < 0.01, P < 0.01; LDH: 5821.53 +/- 163.69 IU/L vs 3015.44 +/- 253.01 IU/L, 2448.75 +/- 169.4 IU/L, P < 0.01, P < 0.01; MPO: 2.57 +/- 0.13 U/g vs 2.13 +/- 0.13 U/g, 2.07 +/- 0.05 U/g, P < 0.01, P < 0.01; NO: 78.39 +/- 2.28 micromol/g protein vs 71.11 +/- 1.73 micromol/g protein, 68.58 +/- 1.95 micromol/g protein, P < 0.05, P < 0.01). The activity of SOD (361.75 +/- 16.22 U/mg protein vs 263.19 +/- 12.10 U/mg protein, P < 0.01) in the liver tissue was decreased after I/R, which was enhanced by VnA pretreatment (263.19 +/- 12.10 U/mg protein vs 299.40 +/- 10.80 U/mg protein, 302.09 +/- 14.80 U/mg protein, P < 0.05, P < 0.05). Simultaneously, the histological evidence of liver hemorrhage, polymorphonuclear neutrophil infiltration and the overexpression of ICAM-1 and E-selectin in the liver tissue were observed, all of which were attenuated in the VnA pretreated groups.

CONCLUSIONS

The results demonstrate that VnA pretreatment exerts significant protection against hepatic I/R injury in rats. The protective effects are possibly associated with enhancement of antioxidant capacity, reduction of inflammatory responses and suppressed expression of ICAM-1 and E-selectin.