Abstract:

Houshiheisan (HSHS) which is created by Zhang Zhongjing, contains two main components of drugs——wind-dispelling drug (WDD) and deficiency-nourishing drug (DND). The compatibility of WDD and DND has adequately showed the theory of “reinforcing the weak body and expelling the pathogenic factor of excess type”. In this study, we investigated the mechanisms of HSHS and its components in axonal remodeling after cerebral ischemia by observing pathological changes and detecting the expression of some relevant proteins. Rats were randomly divided into 5 experimental groups as follow: sham operation group (Sham, n = 12), pMCAO group (pMCAO, n=15), HSHS group (HSHS, n=15), WDD group (WDD,n=15) and DND group (DND, n=15). All drugs were given by intragastric administration respectively, and
the dosage of HSHS, WDD and DND were 10.5g/kg, 7.7g/kg and 2.59g/kg. Suture method was used for permanent occlusion of middle cerebral artery (pMCAO) model to simulate focal cerebral ischemia. Neurological function score and balance beam walking test were performed after pMCAO as neuroethological assessments. HE staining and transmission electron microscopy were used for the assessment of neuropathological changes. Immunofluorescence combined with image analysis technique was used to detect the expression of MAP-2. Western blot was conducted to detect the protein expression including amyloid precursor protein (APP), growth associated protein-43 (GAP-43), neurite outgrowth inhibitor protein A (Nogo-A), Rho family small GTPase A (RhoA), Rho-associated kinase 2 (Rock2), netrin-1, Ras-related C3 botulinum toxin substrate 1 (Rac1) and cell division cycle 42 (Cdc42). These results showed that HSHS,WDD and DND exerted their functions in different aspects via down-regulating the expression of APP,Nogo-A, RhoA, Rock2 and up-regulating the expression of GAP-43, netrin-1, Rac1, Cdc42. In conclusion,HSHS, WDD and DND could improve neurological function, reduce the damage of the axon and promote the recovery of axon by regulating Nogo-A/RhoA/Rock2 and Netrin-1/Rac1/Cdc42 after cerebral ischemia.Importantly, these findings could illustrate the synergic mechanism of WDD and DND, and provide experimental evidence for the application of HSHS on stroke. To draw a conclusion of the study, we confirmthat HSHS has a more potent therapeutic effect on focal cerebral ischemia than WDD or DND alone.

Key words: Houshiheisan, Cerebral ischemia, Axonal recovery, Nogo-A/RhoA/Rock2, Netrin-1/ Rac1/Cdc42.