【作者】 李荣；

【导师】 谢光洪；

【作者基本信息】 吉林大学 ， 临床兽医学， 2020， 硕士

【摘要】 子宫内膜炎是一种常见的子宫炎症,常对人和动物的生殖健康造成严重损害。奶牛子宫内膜炎(endometritis)是奶牛产后的常见疾病之一,是导致奶牛繁殖性能下降的主要原因之一,造成了巨大的经济损失。细菌被认为是子宫内膜炎发生的最重要因素,细菌刺激子宫时,大量中性粒细胞可能浸润子宫。脂多糖(LPS)是细菌的主要成分,可以诱导炎症细胞的活化。LPS激活TLR4信号通路,随后导致NF-?B的激活和炎性细胞因子的释放,进而导致子宫内膜损伤。正常情况下,少量的炎症可以帮助宿主清除入侵的病原体。然而,过度的炎症反应会导致子宫内膜损伤。对于子宫内膜炎的防治目前主要还是采用抗生素的治疗,但是耐药性以及副作用一直是难以避免的问题。因此,探索和筛选天然的、副作用小的候选药物防治奶牛子宫内膜炎,是当前研究的热点。近年来,中药对炎症性疾病如子宫内膜炎的作用越来越受到重视,人们通过对鱼腥草、柏芩等研究发现均有良好的抗炎效果。虎杖苷是从虎杖根茎中提取的一种具有抗炎和抗氧化作用的多酚类物质,可能是一种潜在的治疗子宫内膜炎的药物。本研究旨在探讨虎杖苷对脂多糖(LPS)诱导的小鼠子宫内膜炎的保护作用及其机制。通过阴道注射LPS建立小鼠子宫内膜炎模型。收集各组子宫组织,分析组织病理学改变、炎性细胞因子的产生、NF-κB和Nrf2信号通路的激活程度。组织学分析表明,对照组小鼠形态正常。LPS组表现为炎症细胞浸润、内膜上皮充血水肿等严重病理改变。由脂多糖引起的子宫组织病理学改变被虎杖苷明显减弱。与对照组相比,LPS治疗组子宫组织MPO活性明显升高。此外,虎杖苷治疗可显著降低脂多糖诱导的子宫内膜炎小鼠的MPO活性。炎症细胞因子在炎症过程中起着非常重要的作用。LPS组炎性细胞因子TNF-α、IL-6和IL-1β均较对照组显著升高,而虎杖素治疗组炎性细胞因子水平显著降低。此外,LPS组NF-κB p65和IκBα的磷酸化明显增强。虎杖苷以剂量依赖性的方式抑制LPS诱导的NF-κB p65和IκBα的磷酸化。虎杖苷能增强Nrf2和HO-1的表达。以上结果表明,虎杖苷作用机制可能是通过抑制NF-?B信号通路和激活Nrf2信号通路,有助于减轻脂多糖诱导的子宫内膜炎。这为人和动物子宫内膜炎防治药物的开发,提供了理论和实验基础。更多还原

【Abstract】 endometritis,a common inflammation of the uterus,often causes severe damage to human and animal reproductive health.Dairy cow endometritis(endometritis)is one of the common diseases of dairy cows after giving birth.It is one of the main reasons for the decline in the reproductive performance of dairy cows,causing huge economic losses.Bacteria are considered to be the most important factor in the occurrence of endometritis.When bacteria stimulate the uterus,a large number of neutrophils may infiltrate the uterus.Lipopolysaccharide(LPS)is the main component of bacteria and can induce the activation of inflammatory cells.LPS activates the TLR4 signaling pathway,which subsequently leads to the activation of NF-?B and the release of inflammatory cytokines,which in turn leads to endometrial damage.Under normal circumstances,a small amount of inflammation can help the host clear invading pathogens.However,excessive inflammation can cause endometrial damage.The prevention and treatment of endometritis is currently mainly treated with antibiotics,but drug resistance and side effects have always been unavoidable problems.Therefore,exploring and screening natural drug candidates with low side effects to prevent and treat cow endometritis is a hot research topic.In recent years,the role of traditional Chinese medicine on inflammatory diseases such as endometritis has received more and more attention.People have found that they have good anti-inflammatory effects through studies on Houttuynia cordata and Baiqin.Polydatin is a polyphenolic substance extracted from the rhizome of Polygonum cuspidatum with anti-inflammatory and antioxidant effects.It may be a potential drug for the treatment of endometritis.This study aimed to explore the protective effect and mechanism of polydatin on lipopolysaccharide(LPS)-induced endometritis in mice.A mouse endometritis model was established by vaginal injection of LPS.Uterine tissues of each group were collected to analyze histopathological changes,the production of inflammatory cytokines,and the activation degree of NF-κB and Nrf2 signaling pathways.Histological analysis showed that the mice in the control group had normal morphology.The LPS group showed severe pathological changes such as inflammatory cell infiltration,intimal epithelial congestion and edema.The histopathological changes of uterus caused by lipopolysaccharide were significantly weakened by polydatin.Compared with the control group,the MPO activity of uterine tissue in the LPS treatment group was significantly increased.In addition,polydatin treatment can significantly reduce the MPO activity in mice with lipopolysaccharide-induced endometritis.Inflammatory cytokines play a very important role in the process of inflammation.The inflammatory cytokines TNF-α、IL-6 and IL-1β in the LPS group were significantly higher than those in the control group,while the levels of inflammatory cytokines in the Polygonum cuspidatum treatment group were significantly lower.In addition,the phosphorylation of NF-κB p65 and IκBα was significantly enhanced in the LPS group.Polydatin inhibits the phosphorylation of NF-κB p65 and IκBα induced by LPS in a dose-dependent manner.Polydatin can enhance the expression of Nrf2 and HO-1.The above results indicate that the mechanism of polydatin may be through inhibiting the NF-?B signaling pathway and activating the Nrf2 signaling pathway,which helps to reduce lipopolysaccharide-induced endometritis.This provides a theoretical and experimental basis for the development of prevention and treatment drugs for human and animal endometritis.更多还原