异功散通过调控肠道微生物改善痴呆症模型大鼠的认知下降

Yigong San improves cognitive decline in a rat model of Alzheimer's disease by regulating intestinal microorganisms

目的研究异功散对脂多糖(LPS)诱导认知下降大鼠学习记忆能力的影响,并通过肠道微生物分析其作用机制。方法将40只SD大鼠随机分成空白组、模型组、盐酸多奈哌齐组(1.17 mg/kg)和异功散高剂量组(5.25 g/kg)、异功散低剂量组(2.63 g/kg),8只/组。各组灌胃给予相应药物或纯水干预24 d后,除空白组腹腔注射生理盐水外,其余各组每天腹腔注射LPS(0.5 mg/kg)造模,并开始水迷宫评价其学习记忆能力改变;HE染色观察海马病理形态学变化;16S rRNA检测各组肠道微生物物种变化;酶联免疫吸附测定法检测脑组织和血清中IL-6、TNF-α和IL-1β水平。结果与对照组比较,模型组大鼠第5天逃避潜伏期明显延长(P<0.01),穿越平台次数、平台象限活动累积时间和平均游泳速度均下降,其中穿越平台次数具有统计学差异(P<0.05);海马区可见神经细胞排列散乱、神经细胞变性或坏死等病变且细胞损伤病理评分明显升高(P<0.01);脑组织和血清IL-6、TNF-α和IL-1β水平均明显升高(P<0.01);Alph多样性评价指标如ACE、Chao1等均明显升高(P<0.05),在科水平的Prevotellaceae等物种丰度明显降低而Desulfovibrionaceae等物种丰度则升高。与模型组比较,异功散组第5天的逃避潜伏期均明显缩短(P<0.01),高剂量组穿越平台次数具有统计学差异(P<0.05);海马区神经细胞变性或坏死等病变均有好转且细胞损伤病理评分明显降低(P<0.05);脑组织和血清IL-6、TNF-α和IL-1β水平也均明显下降(P<0.01);Alph多样性评价指标如ACE、Chao1等均明显降低(P<0.05),在科水平的Prevotellaceae等物种丰度明显升高而Desulfovibrionaceae等物种丰度则降低。结论异功散改善认知下降大鼠的学习记忆能力和海马病理形态学等病变可能与调控肠道Prevotellaceae等的丰度,以及信号转导、辅因子和维生素的代谢等代谢途径有关。

Objective To investigate the effect of Yigong San(YGS)on learning and memory abilities of rats with lipopolysaccharide(LPS)‑induced cognitive decline and explore its possible mechanism in light of intestinal microbiota.Methods Forty SD rats were randomly divided into control group,model group,donepezil(1.3 mg/kg)group,and high-dose(5.25 g/kg)and low-dose(2.63 g/kg)YGS treatment groups.After 24 days of treatment with the corresponding drugs or water by gavage,the rats in the latter 4 groups received an intraperitoneal injection of LPS(0.5 mg/kg)to establish models of Alzheimer's disease(AD).Water maze test and HE staining were used to evaluate the changes in learning and memory abilities and pathomorphology of the hippocampus.The changes in gut microbial species of the rats were analyzed with 16S rRNA sequencing,and the levels of IL-6,TNF-α,and IL-1β in the brain tissue and serum were detected using ELISA.Results Compared with the AD model group,the YGS-treated rats showed significantly shortened escape latency on day 5 after modeling,reduced neuronal degeneration and necrosis in the hippocampus,lowered pathological score of cell damage,and decreased levels IL-6,TNF-α and IL-1βin the brain tissue and serum.The YGS-treated rats showed also obvious reduction of Alpha diversity indicators(ACE and Chao1)of intestinal microbiota with significantly increased abundance of Prevotellaceae species at the family level and decreased abundance of Desulfovibrionaceae,which were involved in such metabolic signaling pathways as cell community prokaryotes,membrane transport,and energy metabolism.Conclusion YGS improves learning and memory abilities and hippocampal pathomorphology in AD rat models possibly by regulating the abundance of intestinal microbial species such as Prevotellaceae to affect the metabolic pathways for signal transduction,cofactors,and vitamin metabolism.