Improvement effect and mechanism of calycosin on acute inflammatory injury secondary to intracerebral hemorrhage / 中国药房

ABSTRACT

OBJECTIVE To investigate the improvement effect and mechanism of calycosin （CA） on acute inflammatory injury secondary to intracerebral hemorrhage. METHODS Male C57BL/6 mice were injected with type Ⅶ collagenase into the basal ganglia to establish an intracerebral hemorrhage model， which were divided into sham-operation group（phosphate buffered saline instead of collagenase）， model group， and different CA dose groups（15，30，60，120 mg/kg）. Based on the modified neurological severity score （mNSS） to screen the intervention doses， the volume of intracerebral hemorrhage， brain water content， the expressions of ionized calcium-binding adaptor molecule 1 （Iba1） in brain tissue， Toll-like receptor 4 （TLR4） and its downstream inflammatory factors [tumor necrosis factor-α （TNF-α）， inducible nitric-oxide synthase （iNOS）， interleukin-1β （IL- 1β）] in brain tissue， and the apoptosis of cells in brain tissue were detected. Primary microglia were cultured in vitro， and the expressions of TLR4 and its downstream inflammatory factors were detected. Primary neurons and primary microglia were co- cultured in vitro， and the apoptosis of neurons was detected. RESULTS The doses of 30 mg/kg and 60 mg/kg were selected as intervention doses of CA for subsequent experiments. Compared with the sham-operation group， the mice in the model group had cerebral hemorrhage， the volume of cerebral hemorrhage and brain water content were significantly increased （P＜0.05）； the positive expression rate of Iba1 protein in brain tissue was significantly increased， and the relative expression levels of TLR4， TNF-α， IL-1β and iNOS protein in brain tissue were up-regulated significantly. The apoptosis rate also increased significantly （P＜0.05）. Compared with model group， the above indexes of the mice in the 30 and 60 mg/kg CA groups were significantly improved （P＜0.05）. CA significantlyreduced the relative expression levels of TLR4 and its downstream inflammatory factors in microglia， and reduced the apoptosis of neurons in the co-culture system of primary neurons and primary microglia （P＜0.05）. CONCLUSIONS CA can exert a protective effect on the brain， which may be related to relieving the secondary acute inflammatory injury after intracerebral hemorrhage by inhibiting TLR4-mediated inflammatory response.