Protective effects of polysaccharide extracts from Hibiscus manihot inhibiting oxidative stress response on myocardial ischemia reperfusion injury in rats

Abstract

Objective To investigate the protective effects of polysaccharide extracts from Hibiscus manihot inhibiting oxidative stress response on myocardial ischemia reperfusion injury (MIRI) in rats. Methods Twenty-five SPF rats were randomly divided into 5 groups: the sham operation group, ischemia reperfusion group, low-dose, medium-dose and high-dose Hibiscus manihot groups (25, 50 and 75 mg/kg of polysaccharide extracts from Hibiscus manihot) , with 5 rats in each group. The Hibiscus manihot groups were intragastrically administered before operation. The other two groups were given the same volume of distilled water. Then, the MIRI animal model was prepared by ligation of the left coronary artery. The levels of superoxide dismutase (SOD) , glutathione peroxidase (GSH-Px) , malondialdehyde (MDA) and catalase (CAT) in serum and myocardial tissues in each group were determined. Serum creatine kinase (CK) , activity of lactate dehydrogenase (LDH) and protein expression of NF-κB in myocardial tissues were also determined. Results Compared with the ischemia reperfusion group, the serum MDA levels [ (15.24±2.17) nmol/mL, (14.46±2.87) nmol/mL and (13.87±2.72) nmol/mL], CK activity [ (132.17±18.72) U/mL, (129.55±14.30) U/mL and (126.55±19.36) U/mL] and LDH activity [ (264.63±22.83) U/L, (259.35±22.70 U/L and (254.02±25.29) U/L] in the low-, medium- and high-dose Hibiscus manihot groups significantly reduced, whereas the levels of SOD [ (27.27±4.28) U/mL, (29.36±5.11) U/mL and (28.30±4.83) U/mL], CAT [ (23.33±3.46) U/mL, (25.46±3.04) U/mL and (25.49±3.60) U/mL] and GSH-Px [ (1529.37±227.69) U, (1563.96±260.81) U and (1631.64±255.49) U] significantly increased (P<0.05) . Compared with the ischemia reperfusion group, the MDA levels in myocardial tissue of the low-, medium- and high-dose Hibiscus manihot groups significantly decreased, whereas the levels of SOD, CAT and GSH-Px significantly increased (P<0.05) , and the NF-κB protein expression was significantly down-regulated (P<0.05) . Conclusion The polysaccharide extracts from Hibiscus manihot shows significantly inhibitory effect on the oxidative stress response induced by MIRI in rats, which favor the reduce of myocardial enzymes release and myocardial protection. Key words: Polysaccharide; Myocardial ischemia; Oxidative stress; Extract; Hibiscus manihot