Abstract
This study aimed to investigate the effects of lactuside B (LB) on aquaporin-4 (AQP4) and caspase-3 mRNA expression in the hippocampus and the striatum following cerebral ischaemia-reperfusion (I/R) injury in rats. Cerebral I/R injury was established in Sprague-Dawley rats by occluding the middle cerebral artery for 2 h and then inducing reperfusion. Rats in the I/R + LB groups were treated with various doses of LB following reperfusion. Neurological deficit scores and brain water content were obtained to determine the pharmacodynamics of LB. Reverse transcription polymerase chain reaction was performed to determine the expression levels of AQP4 and caspase-3 mRNA in the hippocampus and the striatum. The results of the present study indicate that LB decreased the neurological deficit scores and the brain water content. In the hippocampus, AQP4 and caspase-3 mRNA expression levels were significantly downregulated in the I/R + LB groups at 24 and 72 h following drug administration, compared with those in the I/R group (P<0.05). In the striatum, LB was also shown to significantly reduce AQP4 and caspase-3 mRNA expression levels at 24 and 72 h following drug administration, compared with those in the I/R group (P<0.05). The effects became stronger as the LB dose was increased. The most significant reductions in AQP4 and caspase-3 mRNA expression were noted in the I/R + LB 25 mg/kg and I/R + LB 50 mg/kg groups at 72 h following drug administration. The results of the present study show that LB is capable of significantly downregulating AQP4 and caspase-3 mRNA expression in the hippocampus and striatum following cerebral I/R injury in rats. The mechanism by which LB improved ischaemic brain injury may be associated with changes in AQP4 and caspase-3 mRNA expression in the hippocampus and the striatum.