Based on Dll4/Notch1 Signaling Pathway to Elucidate the Therapeutic Effect and Mechanism of L-borneolum on Cerebral Ischemic Stroke Rats

Abstract Background: The current research progress suggests that a single therapy may not be ideal means for complex cerebral ischemic stoke (CIS). l -Borneolum is the crystallization of fresh leaves of Blumea balsamifera (L.) DC, we have found that l -borneolum plays a best anti-cerebral ischemic effect than d-borneolum or synthetic borneolum. However, the mechanism is needed to be explored in depth. Therefore, based on comprehensive approach that combines molecular docking technology and molecular biology, this stiudy aimed to investigate the potential mechanism of l -borneolum on CIS rats and provide scientific evidence for the treatment of l -borneolum in CIS. Methods: Cerebral ischemic stroke (CIS) rats with permanent middle cerebral artery occlusion (pMCAO) were applied to this study. The modified neurological severity scores (mNSS) and Longa neurological function scoring methods were used to assess the neurobehavioral scores. 2,3,5-Triphenyltetrazolium chloride (TTC) staining and hematoxylin-eosin (HE) staining were used to evaluate pathological changes of cerebral tissue. Ultrastructure of cortical capillary and blood-brain barrier (BBB) in rats were observed by transmission electron microscopy. In addition, the protein expression of Notch1, Dll4, Hey1, Hes1, Hes5, VEGFA and p65 in the cortex of rats were determined by Western blotting (WB). The protein contents of Caspase 3 in the cortex of rats were determined by immunohistochemical method (IHC). Results: l -Borneolum could prolong the resuscitation time, reduce the abnormal increased rectal temperature, improve neurological function in a dose-dependently. Additionally, l -borneolum could significantly alleviate brainstem edema and inflammation, as well as improve the ultrastructure of capillary and BBB in cortex. Moreover, 0.2 g/kg l -borneolum could substantially decrease the protein expressions of Dll4, Notch1, Hes1, Hes5, and VEGFA in the cortex while it decreased the level of Caspase-3 in the cortex of rats. Conclusions: l -Borneolum could repair neurological function by regulating Dll4/Notch1 signaling pathway, l -borneolum might be a good complementary agent for CIS.