Experimental Study of Tongqiao Huoxue Decoction on Neuroprotection after Cerebral Ischemia in Rats by Activating Shh Signaling Pathway

To investigate the neuroprotective effect of Tongqiao Huoxue Decoction on cerebral ischemic rats and explore its mechanism through the Shh signaling pathway. 72 SD rats were randomly divided into six groups: Sham surgery group (6 g• kg-1), model group (6 g• kg-1), NMDP group (10 mg• kg-1), TQHXD low-, medium and high-dose groups (2.9, 5.8, 11.6 g• kg-1). Drug intervention was carried out on the rats in each group 7 days before modeling, and the cerebral ischemia model of rats was established by the modified Zea-Longa suture method. 24 hours after modeling success, samples were taken, and the memory ability (behavioral function) of rats was measured by Morris water maze, The Zea-Longa scoring method was used to measure neurological function, and HE staining method was used to observe brain tissue pathology, TUNEL method was used to detect the apoptosis rate of Cranial nervescells, immunohistochemical method was used to detect the expression of protein of caspase-3,Shh, Gli1, and Western blot was used to detect the expression of Shh, Gli1 protein. The results showed that compared with the Sham surgery group, not only the time of searching for the platform in the model group was significantly prolonged (P<0.05), but also crossing the platform were greatly reduced (P<0.05), the hippocampal neuronal tissue structure was damaged, and the neuronal apoptosis rate in the hippocampus was significantly increased (P<0.01). In addition, the expression of Shh and Gli1 (immunohistochemistry, Western blot) proteins increased (P<0.05), and caspase-3 (immunohistochemistry) proteins also increased. Compared with the model group, rats in the NMDP group and TQHXD three dose groups showed greatly shorter platform search times (P<0.05) and more times of crossing the platform (P<0.05). The morphology and structure of hippocampal neurons showed varying degrees of improvement. The expression of Shh and Gli1 (immunohistochemistry, Western blot) proteins in the hippocampus of the NMDP group, TQHXD medium dose group, and TQHXD high-dose group increased (P<0.01). Besides, the apoptosis rate of hippocampal neurons marked decline(P<0.01), and the expression of caspase-3 (immunohistochemistry) protein descended. In summary, pretreatment with Tongqiao Huoxue Decoction can improve neural function in rats with cerebral ischemia, possibly by activating the Shh signaling pathway and reducing neuronal apoptosis.