The Kinesis Change Of CKs, Hormones And HSP70 In Cold Stressed Piglets

To investigate the effects of acute cold stress on the immune functions in swine, eighteen"Yorkshire"piglets aged 45d were randomly divided into normal temperature control group (control, C), the cold-exposed group (cold exposure, CE) and exposed to cold along with glucocorticoid receptor blocker injected (cold exposure + RU486, CER). Normothermia group in the 18 to 20℃and cold-exposed groups in the 4 to 8℃for 12 hour. Blood samples were collected at 0 h, 1 h, 3 h, 6 h, 9 h, 12 h after cold exposured from piglet's superior vena cava. Plasma and peripheral blood mononuclear cells (PBMC) were separated and stored in -80℃.Cytokines (cytokines, CKs) of plasma samples were detected by double-antibody sandwich ELISA; ACTH and cortisol levels of the plasma samples were detected by RIA;The relative expression of HSP70 of PBMC were detected by western-blotting detection methods.Explored the dynamic changes of the law of IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γand IgG, stress hormones level and relative expression of HSP70 of PBMC in three cases.Results (1) Most of serum cytokines and IgG concentration appeared the trend seems that increased first and reduced later,the first time point of cytokines and IgG significant increasing were the receptor antagonist group,the control group, and the group exposed to cold in order.But TNF-αconcentration reduced fist and recover later ,the group exposed to cold reached the lowest point first ,then followed with the control and the receptor antagonist group.(2) Level of ACTH of each group fluctuated, the overall trend of it were lower than before the experiment; levels of cortisol also fluctuated and have no significance, but only the cold-exposed group at 3 h were significantly higher(P<0.01). (3) HSP70 of each group were significantly increased at the start 1 h exposed to cold, which receptor antagonist group were significantly higher, and then, the control group and simply exposed to cold group HSP70 were slow fluctuations, and the receptor antagonist group HSP70 first significant dropped then made a marked increase later. Results suggest that in acute cold stimulation conditions, the body combat stress reaction is positive, the performance enhanced the secretion of cytokines,the release of cortisol, as well as the expression of HSP70, but along with time lasting, those effects were disappeared and the levels tend to normal. From the correlation analysis,we can speculated that HSP70 in PBMC affectted production and secretion of cytokines might be closely linked with GRs.