RESUMO
Objective Paeoniflorin ( PAE) is a potential neuroprotective agent.In this study, we investigated the protective effect of PAE on cerebral ischemia/reperfusion ( CI/R) injury in gerbils and its underlying mechanisms. Methods The model of CI/R was established in 50 gerbils by bilateral common carotid occlusion for 10 min followed by 6-hour reperfusion.Then the animals were equally randomized into five groups:sham, model, 5 mg/kg PAE, 10 mg/kg PAE, and 20 mg/kg PAE.The latter three groups were treated with intraperitoneal injection of PAE once daily for 3 days before carotid occlusion, while the former two groups with saline only, all at 10 ml/kg.Stroke indexes were calculated during the reperfusion.The contents of endogenous neuropeptides, endothelin and calcitonin gene-related peptide ( CGRP) in the plasma were measured by radioimmunoassay.The levels of superoxide dismutase ( SOD) and malondialdehyde ( MDA) in the brain tissue homogenate were determined by the method of xanthine oxidase. Results The 5, 10, and 20 mg/kg PAE groups showed significantly decreased stroke index (14.8 ±3.6, 12.3 ±2.0, and 12.7 ±1.4) as compared with the model group (18.4 ±2.9) (P<0.05), but remarkably increased SOD activity ([99.30 ±9.71], [106.85 ± 15.13] , and [110.25 ±14.90] vs [86.54 ±10.22] nU/mgPro, P<0.05) .The MDA content was significantly lower in the 10 and 20 mg/kg PAE groups than in the model group ([69.23 ±8.42] and [65.91 ±7.64] vs [94.76 ±10.30] μmol/mgPro, P<0.01). The plasma endothelin level was markedly decreased in all the PAE groups in comparison with the model group ([24.06 ±5.37], [19.62 ±5.60] and [21.08 ±4.64] vs [30.52 ±7.13] ng/L, P<0.05). Conclusion The protective effect of PAE pretreatment in CI/R injury appears to be associated with the inhibition of the brain free radicals, lipid peroxidation and endothelin production.
