Effects of lycium barbarum polysaccharides on neuropeptide Y and heat-shock protein 70 expression in rats exposed to heat.

The purpose of the present study was to investigate the effects of high ambient temperature on the neuropeptide Y (NPY) mRNA level in the hypothalamus, the plasma concentration of corticotropin-releasing hormone (CRH), cortisol (Cor), heat-shock protein 70 (HSP70) and epinephrine (EPI), and the intervention of lycium barbarum polysaccharides (LBPs) in rats. Compared to the control (CN) group, the plasma levels of CRH, Cor, HSP70 and EPI were markedly increased, and the level of NPY mRNA was downregulated in the high ambient temperature (HT) group. By contrast, rats in the HT + LBP (HTL) group had: i) a significantly enhanced expression of HSP70 compared to the HT and CN groups; ii) clearly increased plasma levels of CRH, Cor and EPI compared to the CN group; and iii) a markedly upregulated expression of NPY mRNA compared to the HT group. Thus, the results showed that high-temperature environments may damage the body, and LBPs have a potentially protective function by increasing the expression of HSP70 and NPY.