枸杞多糖对热暴露大鼠血浆CRH、Cor、HSP70含量及下丘脑NPY mRNA表达的影响

Effects of LBP on CRH,Cor,HSP70 and Expression of NPY mRNA in Rats Exposed to Heat

目的热暴露对大鼠应激器官重量和血浆中促肾上腺皮质激素释放激素(corticotropin-releasing hormone,CRH)和皮质醇(cortisol,Cor)和热休克蛋白70(heat shock 70 protein,HSP70)含量以及下丘脑神经肽Y(neuropeptide Y,NPY)mRNA表达水平的影响及枸杞多糖(lycium barbarum polysacharides,LBP)干预作用。方法雄性SD大鼠随机分为正常对照组(CN)、热暴露组(HE)及枸杞多糖干预组(HL)。对照组置于24℃人工环境下饲养,热暴露组与枸杞多糖干预组均置于32℃的人工环境中。经14d热暴露后,取脾脏、肝脏、胸腺、下丘脑器官精确称重;检测血浆中CRH、Cor和HSP70的含量;测定大鼠下丘脑NPY mRNA的表达水平。结果与对照组相比,热暴露组和枸杞多糖干预组大鼠的肝脏器官相对重量明显降低(P<0.05),血浆CRH、Cor及HSP70的含量明显升高(P<0.05);热暴露组大鼠NPY mRNA表达水平升高(P<0.05)。与热暴露组比较,枸杞多糖干预组大鼠的血浆HSP70含量升高(P<0.05),NPY mRNA表达水平降低(P<0.05)。3组大鼠脾脏、胸腺和下丘脑的器官相对重量无明显变化(P>0.05)。结论枸杞多糖可使应激大鼠血浆中热休克蛋白70含量升高,下丘脑NPY mRNA表达下调,因此枸杞多糖对热暴露环境下的机体有保护作用。

Objective To investigate heat exposure on weight of stress organ and the content of corticotropin - releasing hormone（ CRH）, cortisol（ Cor）, heat shock 70 protein（HSP70） and neuropeptideY （NPY） gene expression in hypothalamus and intervention of lycium barbarum polysacharides （LBP） in Rats. Methods Five -week -old SD male rats were randomly divided into control （CN）, heat exposure （HE） and heat expo- sure ＋ LBP （HL） group. Rats were kept in a room with temperature （24 ± 1 ） ℃, relative humidity of（60 ＋±5 ） % in CN group, while the rats were exposed to （32 ± 1 ） ℃, relative humidity of （60 ± 5 ） % in HL and HE group. The spleen, liver, thymus, hypothalamic and pituitary were picked up and weighed accurately a.f-ter 14 days heat exposure; moreover, the plasma levels of CRH, Cor, and HSP70 were detected by enzyme linked immunosorbent assay and mRNA expression of NPY was determined by RealTime Quantitative PCR. Results Compared with the CN group, in HE group and HL group, the relative weight of liver significantly was reduced （ P 〈 0.05 ）, the plasma levels of CRH, Cor and HSP70 was significantly increased （P 〈 0.05 ） ; the expression of NPY mRNA was increased in HE group （ P 〈 0.05 ）. Compared with the HE group, in HL group, the plasma levels of HSP70 was increased （ P 〈 0.05 ）, the ex-pression of NPY mRNA was remarkably decreased （P 〈 0.05 ）. However, among the three groups, the rela-tive weight of spleen, thymus and hypothalamic had no obvious change （ P 〉 0.05 ）. Conclusion In the process of heat exposure, rats were into the stress state. Due to the increased levels of HSP70 and decreased expression of NPY mRNA, LBP have a potential protective function to the body.