Protective effects of Tongxinluo on cerebral ischemia/reperfusion injury related to Connexin 43/Calpain II/Bax/Caspase-3 pathway in rat

Tongxinluo (TXL) is a multifunctional traditional Chinese medicine and has been widely used in the treatment of cardiovascular and cerebrovascular diseases. Numerous studies demonstrate that TXL is a novel neuroprotective drug, however, the mechanisms are largely unknown. we aimed to demonstrate the protective effect of TXL on cerebral ischemia/reperfusion (I/R) injury and provide the evidence for the involvement of Connexin 43/Calpain II/ Bax/Caspase-3 pathway in TXL-mediated neuroprotection. Focal cerebral I/R injury were induced by transient middle cerebral artery occlusion (MCAO, for 90min) in adult male Sprague-Dawley rats. We estimated the effects of TXL on I/R injury including neurological deficit assessment and cerebral infarct volume measurement via TTC staining, and detected the protein expression of Connexin 43 (Cx43) by western blot. Furthermore, after the intracerebroventricular injection of carbenoxolone (CBX, the inhibitor of Cx43) at 30min before MCAO surgery, Calpain II, Bax and cleaved Caspased-3 immunoreactivity in ischemic penumbra region was detected by immunofluorescent staining, and cell apoptosis was detected by TUNEL staining. TXL treatment greatly improved neurological deficit and reduced the infarction volume compared to MCAO with buffer treatment (P