异虎耳草素通过调控Nrf2-NF-κB通路轴减轻松果体损伤大鼠氧化应激和炎症反应

Isopimpinelline mitigates the oxidative stress and inflammation triggered by pineal gland damage through inhibiting NF-κB signaling pathway

目的探讨异虎耳草素对PCPA诱导的大鼠松果体损伤的保护作用及其机制。方法将40只雄性SD大鼠随机分为正常组,模型组,褪黑素10 mg/kg组和异虎耳草素1.5 mg/kg组,每组10只。除正常组外,其余3组均通过腹腔注射PCPA(450 mg/kg)构建松果体损伤大鼠模型,造模成功后灌胃给药,连续7 d。在给药第6天,采用戊巴比妥钠协同睡眠实验评估各组大鼠的入睡潜伏期和睡眠持续时间。给药结束后,检测血清褪黑素、松果体组织超氧化物歧酶(SOD)、丙二醛(MDA)、谷胱甘肽(GSH)、谷胱甘肽过氧化物酶(GPx)、过氧化氢酶(CAT)、一氧化氮(NO)、白介素(IL)-6、IL-2和肿瘤坏死因子(TNF-α)含量;HE染色观察松果体组织病理学变化;Western blot法检测松果体组织中血红素加氧酶1(HO-1)、醌氧化还原酶1(NQO-1)、核因子E2相关因子2(Nrf2)、Kelch样ECH相关蛋白1(Keap1)、核转录因子-κB(NF-κB)p65、IκB激酶β(IKKβ)、磷酸化IκB激酶β(p-IKKβ)蛋白表达。结果与正常组比较,模型组大鼠松果体细胞结构损伤严重、数目减少,大鼠入睡潜伏期延长,睡眠持续时间缩短,褪黑素、SOD、GSH、GPx和CAT含量降低,NO、MDA、IL-2、TNF-α和IL-6含量升高(P<0.05),Nrf2、NQO1、HO-1、NF-κB p65、IKKβ、p-IKKβ和核NF-κB p65蛋白表达上调,Keap1和胞质NF-κB p65表达下调(P<0.05);与模型组比较,异虎耳草素组大鼠松果体组织损伤得到缓解,入睡潜伏期和睡眠持续时间明显改善,褪黑素、SOD、GSH、GPx和CAT含量增加,NO、MDA、IL-2、TNF-α和IL-6含量减少(P<0.05),Nrf2、NQO1、HO-1、NF-κB p65、IKKβ、p-IKKβ和核NF-κB p65蛋白表达下调,Keap1和胞质NF-κB p65表达上调(P<0.05)。结论异虎耳草素能够通过激活Nrf2信号通路和抑制NF-κB信号通路,抑制氧化应激和炎症反应,减轻大鼠松果体组织损伤,促进褪黑素分泌。

This study was designed to investigate the potential protective effect of isopimpinelline against para-chlorophenylalanine(PCPA)-induced pineal gland damage in rats.Forty male Sprague-Dawley(SD)rats were divided into four groups(n=10 each):a normal group,a model group,a melatonin-treated group(10 mg/kg),and an isopimpinelline-treated group(1.5 mg/kg).All groups,except for the normal,received intraperitoneal injection of PCPA(450 mg/kg)to induce pineal gland damage.Subsequent treatments were administered orally for 7 days.Sleep latency and duration were evaluated on the sixth day using the pentobarbital sodium sleep synergy test.After the treatment period,serum melatonin levels and pineal gland inflammation markers were assessed alongside oxidative and antioxidative parameters.Histological examinations of the pineal gland were conducted,and the expression of proteins related to the Nrf2 and NF-κB signaling pathways were quantified.Data showed that isopimpinelline alleviates the structural damage in the pineal gland of model rats,significantly elevated serum melatonin levels,and markedly improved sleep latency and duration(P<0.05).Isopimpinelline activated the Nrf2 signaling pathway by inhibiting Keap1 expression,which facilitated the nuclear translocation of Nrf2 and upregulated the antioxidant proteins NQO1 and HO-1,thereby mitigating oxidative stress in the pineal gland(P<0.05).Furthermore,isopimpinelline significantly reduced the levels of pro-inflammatory cytokines IL-2,TNF-αand IL-6.Isopimpinelline also suppressed the NF-κB signaling pathway,reducing the expression of NF-κB p65,IKKβ,and p-IKKβproteins,as well as the nuclear translocation of NF-κB p65(P<0.05),thereby providing anti-inflammatory benefits.In conclusion,isopimpinelline could protect pineal gland from damage by activating the Nrf2 signaling pathway and inhibiting the NF-κB pathway.