Protective effects of total flavones of rhododendra against global cerebral ischemia reperfusion injury.

The purpose of this research was to demonstrate the protective effects and possible mechanisms of total flavones of rhododendra (TFR) against global cerebral ischemia reperfusion injury in rats. Global cerebral ischemia/reperfusion injury was caused by four vessel occlusion (bilateral vertebral arteries and bilateral carotid arteries, 4-VO). The electroencephalographic (EEG) changes were recorded. The EEG, brain water content, levels of malondialdehyde (MDA) and lactate dehydrogenase (LDH) activity in plasma, aggregation of platelets induced by ADP, and the resting and CaCl(2)-induced increase of free intracellular calcium concentration ([Ca(2+)](i)), were also evaluated. TFR dramatically elevated EEG amplitude, reduced the brain water content and the resting cytoplasmic free calcium concentration, inhibited the increase of [Ca(2+)](i) induced by CaCl(2) and had an inhibitory effect on platelet aggregation. The LDH activity and the MDA content in plasma were also decreased. These results indicate that TFR has protective effects against cerebral injury in rats, which might be associated with its antioxidant properties, antiplatelet effects and possible inhibition of Cal(2+) influx to reduce [Ca(2+)](i).