柴胡加龙骨牡蛎汤对抑郁大鼠海马NLRP3通路的免疫调节作用

Immunoregulatory Effect of Chaihu Jia Longgu Mulitang Modified with Bupleuri Radix on Hippocampal NLRP3 Pathway in Depressed Rats

目的:探讨柴胡加龙骨牡蛎汤对抑郁大鼠海马NOD样受体蛋白3(NLRP3)炎症小体通路的作用及其机制。方法:60只雄性SD大鼠随机平均分为6组,分别为正常组、模型组、柴胡加龙骨牡蛎汤高、中、低剂量组,NLRP3抑制剂(MCC950)组。除正常组外,其余采用孤养联合慢性不可预见性应激(CUMS)21 d,制备抑郁大鼠模型。柴胡加龙骨牡蛎汤高、中、低组分别灌胃13,6.5,3.25 g·kg^(-1)柴胡加龙骨牡蛎汤溶液,MCC950组腹腔注射1 mg·kg^(-1),正常组、模型组灌胃等体积生理盐水,给药21 d期间持续追加造模。采用糖水偏好实验(SPT)和新奇摄食实验评价大鼠的抑郁行为,酶联免疫吸附测定法(ELISA)检测海马组织匀浆中白细胞介素-1β(IL-1β)和IL-18含量,蛋白免疫印迹法(Western blot)检测各组大鼠海马中NLRP3,凋亡相关微粒蛋白(ASC)及半胱氨酸天门冬氨酸蛋白水解酶-1(Caspase-1)蛋白表达。结果:与正常组比较,模型组糖水偏好率显著降低(P<0.01),新奇摄食时间显著延长(P<0.01);海马组织中NLRP3,ASC,Caspase-1蛋白表达显著增强(P<0.01),IL-1β和IL-18水平显著升高(P<0.01)。与模型组比较,柴胡加龙骨牡蛎汤高、中组糖水偏好率显著提高(P<0.01),新奇摄食时间显著缩短(P<0.01);海马中NLRP3,ASC,Caspase-1蛋白表达明显减弱(P<0.05,P<0.01),IL-1β和IL-18水平显著降低(P<0.01)。结论:柴胡加龙骨牡蛎汤可减轻CUMS诱导的抑郁行为,其机制可能与抑制NLRP3炎症小体通路有关。

Objective:To investigate the effect and mechanism of Chaihu Jia Longgu Mulitang(CJLM)on hippocampal NOD-like receptor protein 3(NLRP3)inflammasome pathway in rats with depression.Method:Sixty male SD rats were randomly divided into a normal group,a model group,a MCC950(1 mg·kg^(-1))group,and high-(13 g·kg^(-1)),medium-(6.5 g·kg^(-1)),and low-dose(3.25 g·kg^(-1))Chaihu Jia Longgu Mulitang groups,with 10 rats in each group.The depression model was induced by isolation combined with chronic unpredictable mild stimulation(CUMS)in rats except for those in the normal group.Rats were treated correspondingly for 21 days by intraperitoneal injection in the MCC950 group and gavage in other groups.The normal group and the model group received an equal volume of normal saline.The depression-like behaviors of rats were observed by sucrose preference test(SPT)and novelty-suppressed feeding test.Enzyme-linked immunosorbent assay(ELISA)was used to determine the levels of interleukin-1β(IL-1β)and IL-18 in the hippocampus of depressed rats.Western blot was used to detect the protein levels of NLRP3,apoptosisassociated speck-like protein containing a C-terminal caspase recruitment domain(ASC),and Caspase-1.Result:Compared with the normal group,the model group showed decreased sucrose preference rate(P<0.01),prolonged novelty-suppressed feeding time(P<0.01),enhanced protein expression of NLRP3,ASC,and caspase-1(P<0.05,P<0.01),and elevated expression of IL-1βand IL-18(P<0.01).Conclusion:CJLM can alleviate depression-like behaviors in CUMS-induced model rats,and the underlying mechanism is related to the inhibition of the NLRP3 inflammasome pathway.