铜预投对大鼠冷应激性胃溃疡的影响及机制

Effects and possible mechanism of copper pre-administration on rats' gastric ulcer caused by cold stress

目的:探讨铜预投对应激性胃溃疡的影响及可能的机制。方法:28d龄清洁级SD大鼠80只,随机分成4组,即灌水组、低铜组(LC)、中铜组(MC)和高铜组(HC),每组再分应激组和室温对照组;灌胃3w后,采用冷拘束法使大鼠产生应激性胃溃疡,观察胃黏膜溃疡指数,测定血清铜、锌值及超氧化物岐化酶(SOD)活性、还原型谷胱甘肽(GSH)和丙二醛(MDA)含量。结果:①冷应激后各组血清锌含量显著上升,灌水组、LC组和MC组血清铜含量略有下降,HC组血清铜含量则不降反升。②灌水组、LC组、MC组和HC组溃疡指数依次有降低趋势,HC组与灌水组和LC组比较有显著的降低(P<0.05)。③冷应激后各组血清中SOD活性均降低,以MC组和LC组最为明显(P<0.01);GSH含量均极明显升高(P<0.01);MDA含量均略有升高。结论:冷应激能影响大鼠血清中铜锌含量和Cu/Zn比值,适量的铜给予对应激性胃溃疡有保护作用;其机制可能与铜提高了血清中SOD活性和GSH含量,从而增强机体的自由基清除能力有关。

Objective To explore the effects and possible mechanism of copper pre-admin- istration on stress ulcer. Methods: 80 SD rats of 28 days old were divided into 4 groups at random, namely feeding water group, low copper group (LC), moderate copper group (MC), and high copper group (HC), feeding the four groups with deionized water, lower, moderate, and higher dose of copper respectively by intragastric administration for 3 weeks. Each group was randomly divided into ambient temperature contrasting groups and cold stress groups. The rats in the cold stress groups suffered from induced gastric ulcer. Gastric mucosa ulcer index, concentration of serum copper and serum zinc, activity of superoxide dismutase (SOD), reduced glutathione (GSH) and malondialdehyde (MDA) were observed and analyzed for each group. Results: ① The concentration of serum zinc of cold stress groups was markedly higher than that of ambient temperature contrasting groups. The concentration of serum copper in LC group, MC group of cold stress groups were slightly lower, and HC group slightly higher than that of ambient temperature contrasting groups. ② Gastric mucosa ulcer index of cold stress group was rising in the following order: Feeding water group; LC group; MC group and HC group. The gastric mucosa ulcer index was significantly degraded in the HC group compared to in the feeding water group. ③Compared to ambient temperature groups, activity of SOD in all cold stress groups decreased, especially in the MC group and LC group (P<0.01). Content of GSH in all cold stress groups was greatly heightened and content of MDA in all cold stress groups was slightly increased. By comparison between each group, in the feeding water group was the highest and MC group was the lowest, the difference between two groups was significant. Conclusion: Cold stress can affect the ratio of Cu/Zn in serum, and appropriate copper administration can be protective against gastric ulcer. The mechanism of this function is potentially that copper enhances the activity of SOD and increases the content of GSH, accordingly this promotes the capability to clean free radicals in the organism.