Effects Of Bombesin On The Expression Of HSP70,TRPM8,TNF-α And Correlation Under Cold And Heat Stress

ObjectiveBombesin（BN）is widely found in mammals,including humans,with a strong body temperature lowering.The cooling effect of BN is different from the negative regulation medium of body temperature.It can not only reduce the body temperature during fever,but also reduce the normal body temperature.The cooling effect of BN may be achieved by affecting the synthesis and release of some mediators in the normal regulation path of body temperature.BN has the potential to become a more safe and effective antipyretic agent than a high-dose chemical antipyretic.However,it is unclear about the regulatory role of BN on body temperature under cold and cold stress and its effect on the expression of related factors,leading to the lack of sufficient theoretical basis for its wide range of clinical applications.Studies have shown that long-term fever or high fever can cause an increase in HSP70 synthesis in the hypothalamic thermoregulation center,which increase the tolerance of cells to damage and achieve the purpose of maintaining normal functional metabolism.TRPM8 by regulating the intracellular Ca²⁺、Na⁺concentration and membrane potential participate in cold sensation,pain perception,inflammatory response,in order to regulate the body’s body temperature and homeostasis.It,as an endogenous TNFα,can cause fever by stimulating inflammatory factors such as IL-1and IL-6 such as hypothalamic body temperature regulation center and macrophages,and the TNF-αlevel is positively correlated with the fatality rate of some clinical diseases,especially the TNF-αcontent is significantly increased in the serum of heat shock patients.This study discusses the influence of BN on the expression of HSP70,TRPM8 and TNF-α,discusses the mechanism of BN reducing body temperature under stress,lays the theoretical foundation for the application of BN in the clinical treatment of heat stroke,heat shock and“unexplained fever”and can provide new ideas for the clinical establishment of some medical activities(such as cryogenic anesthesia,etc.,anti-inflammatory,etc.MethodIn this experiment,male healthy SD rats with 180-220g were fixed into a brain stereocalyser after anesthesia,and lateral intraventricular intubation was performed.Routine feeding one week after surgery restored the rats to their normal body state.Anal temperature was measured continuously 7d before the experiment so that it was applied to the experimenter technique and reduce stress.Body temperature was measured three times before the experiment as the basal body temperature and administered by lateral ventricle intubation,measured every 30min during the period.After the experiment,rats were left dead using scaffold and perfusion,thalamic specimens were removed for immunohistochemistry,Western blot,and Realtime RT-PCR,and the experimental data were analyzed using SPSS22.0 software.ResultsAfter the injection of frog pictin under heat stress,Rats showed a significant decline in body temperature（P<0.05）;HSP70 and TNF-expression was increased in heat stress,It was significantly higher than that in the normal temperature control group（P<0.05）;After the inhibition of HSP70,The expression of TNF-αalso decreased,The two are correlated;Both the BN and the HSP70 inhibitor KNK437 significantly inhibited the HSP70 expression at high temperature（P<0.05）;BN cooling decreased significantly and rapidly under cold stress,Minimum level at 15min;High TRPM8expression was induced by BN under cold stress（P<0.05）;TRPM8 and TNF-αwere negatively regulated under cold stress.ConclusionBombesin can down the body temperature rise caused by high temperature environment,can significantly inhibit body temperature rise,BN is a potential and effective preventive drug of heat stress.HSP70 and TNF-αplay important roles in the thermoregulation of heat stress,and BN can then regulate the body temperature by regulating the expression of HSP70 and TNF-α.BN reduces body temperature rapidly and violently at low temperature environment,TRPM8 and TNF-αare negatively correlated in cold stress,and it is possible that BN can participate in body temperature regulation under cold stress through TRPM8.