A polysaccharide (PNPA) from Pleurotus nebrodensis offers cardiac protection against ischemia-reperfusion injury in rats

In this study, we isolated a polysaccharide (PNPA), with a molecular weight of 105 kDa, from the fruiting bodies of Pleurotus nebrodensis. It had a backbone consisting of 1,3-linked-d-glucpyranosyl and 1,3,6-linked-d-galactopyranosyl residues, which was terminated with 1-linked-d-mannopyranosyl terminal at O-3 position of 1,3,6-linked-d-galactopyranosyl unit along the main chain in the ratio of 4:1:1. We further examined the effect of PNPA on myocardial ischemia-reperfusion (I/R) injury in rats and elucidated the underlying mechanism. Pretreatment with PNPA (100 and 400 mg/kg) for 30 days significantly attenuated myocardial infarct size as compared to I/R model group. A decrease in superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels, as well as an increased malondialdehyde (MDA) content were observed in both myocardial serum and tissues of control I/R group, whereas pretreatment with PNPA markedly restored these change, and also relieved myocardial cell apoptosis. These results suggested that PNPA achieved protective effect on myocardial I/R injury in part through improving endogenous antioxidants and suppressing myocardial cell apoptosis.