瑞马唑仑对脓毒症小鼠认知功能的保护作用及机制

Protective effect and mechanisms of remimazolam on cognitive function in septic mice

目的探究瑞马唑仑对脓毒症小鼠认知功能的保护作用及其机制。方法将54只C57BL/6小鼠随机分为生理盐水组(NS组)、单纯瑞马唑仑组(RM组)、脓毒症模型组[脂多糖(LPS)组]、不同剂量瑞马唑仑脓毒症组(RM_(10)、RM_(15)、RM_(20)组),每组9只。通过腹腔注射1 mg/kg LPS建立脓毒症模型;RM组腹腔注射15 mg/kg瑞马唑仑溶液;RM_(10)、RM_(15)、RM_(20)组在注射LPS前30 min分别腹腔注射10、15、20 mg/kg瑞马唑仑溶液。记录Morris水迷宫实验中各组小鼠穿越平台次数和停留第一象限时间百分比;ELISA法检测外周血和脑海马肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)水平;化学比色法检测脑海马丙二醛(MDA)、还原型谷胱甘肽(GSH)水平和超氧化物歧化酶(SOD)活性;HE染色观察海马CA1区神经元病理变化。结果LPS组小鼠穿越平台次数、第一象限停留时间百分比、GSH水平、SOD活性明显下降,TNF-α、IL-1β和MDA水平明显升高。HE染色可见海马CA1区神经元数量减少、排列紊乱、细胞质染色加深伴细胞核固缩深染。与LPS组比较,不同剂量瑞马唑仑组小鼠穿越平台次数、第一象限停留时间百分比、GSH水平、SOD活性增加,TNF-α、IL-1β和MDA水平降低,海马CA1区变性神经元减少。不同剂量瑞马唑仑组之间比较,RM_(20)组小鼠改善脓毒症小鼠认知功能障碍和炎症氧化应激的程度均低于RM_(10)组和RM_(15)组。结论瑞马唑仑对脓毒症小鼠认知功能障碍具有一定的保护作用,其机制可能与其结合转位蛋白(TSPO)抑制巨噬细胞极化,从而减轻神经炎症和氧化应激损伤有关,其中10、15 mg/kg瑞马唑仑比20 mg/kg瑞马唑仑的保护效果更明显。

Objective To study the protective effect and mechanism of remimazolam on cognitive function in septic mice.Methods Fifty-four C57BL/6 mice were randomly divided into saline group(NS group),simple remimazolam group(RM group),sepsis model group[lipopolysaccharide(LPS)group]and sepsis groups with different doses of remimazolam injection(RM_(10),RM_(15)and RM_(20)groups).The sepsis model was established by intraperitoneal injection of 1 mg/kg LPS;the RM group was injected intraperitoneally with 15 mg/kg remimazolam solution;the RM_(10),RM_(15)and RM_(20)groups were respectively injected with 10,15 and 20 mg/kg remimazolam solution 30 mins before LPS injection.The number of times the mice crossed the platform and the percentage of time they stayed in the first quadrant were recorded in the Morris water maze experiment;the levels of tumor necrosis factor-α(TNF-α)and interleukin-1β(IL-1β)in peripheral blood and hippocampus were measured by enzyme-linked immunosorbent assay(ELISA);the levels of malondialdehyde(MDA),glutathione(GSH)and superoxide dismutase(SOD)activity in hippocampus were measured by chemical colorimetric assay;and the pathological changes of neurons in CA1 area of hippocampus were observed by Hematoxylin-eosin(HE)staining.Results In the LPS group,the number of platform crossing times,the percentage of staying time in the first quadrant,GSH level and SOD activity significantly decreased,and TNF-α,IL-1βand MDA levels significantly increased.In addition,the arrangement of neurons in CA1 area of hippocampus was disturbed;cytoplasmic staining was deepened;and the nucleus was solidly stained.Comparing RM_(10),RM_(15)and RM_(20)groups with the LPS group,the number of platform crossing times,the staying time in the first quadrant,GSH level and SOD activity increased,and the levels of TNF-α,IL-1βand MDA decreased.And the results of hippocampal staining showed a decrease in degenerated neuronal cells.When it came to the comparision in the groups with different doses of remimazolam injection,septic mice in the RM_(20)group showed less improvement in cognitive dysfunction and inflammatory oxidative stress than the RM_(10)and RM_(15)groups.Conclusion Remimazolam has a protective effect on cognitive dysfunction in septic mice,and its mechanism may be related to its binding of translocator protein(TSPO)to inhibit macrophage polarization and thus reduce neuroinflammation and oxidative stress damage.It also reflects that dose of 10 mg/kg and 15 mg/kg has more significant protective effect than that of 20 mg/kg.