HSP70 expression in pancreas of rats under the condition of simulated weightlessness

Abstract

Objective To investigate Hsp70 expression features of rat's pancreas under the condition of simulated weightlessness.Methods Tail-suspension method was used to simulate the weightlessness animal model.Sixty four adult male Wistar rats were randomly divided into 8 experimental groups (n =8):suspended for 6 h,12 h,1 d,2 d,3 d,5 d,7 d and control group.Hsp70 protein and mRNA in rat's pancreas were detected by using immunohistochemical assay,Western blot and RT-PCR techniques.Results The immunohistochemistry assay showed that Hsp70 protein was expressed in rats with tail-suspension,in particular the nuclei and cytoplasm of pancreatic islet cells were deeply stained in the early phase of suspension,but was not expressed in rats without tail-suspension.The expressions of Hsp70 protein were 0.881 ±0.013,0.874 ±0.014,0.865 ±0.014,0.837 ±0.012 in 6 h,12 h,1 d,2 d groups,which were significantly higher than those in control group (0.921 ±0.078,P＜0.05),and 0.862 ±0.042,0.838 ±0.063,0.807 ±0.071 in 3 d,5 d,7 d groups,which returned to the level of control group.The expressions of Hsp70 mRNA significantly increased at 6 h,and then gradually decreased,at 3 d they reached the lowest point (0.694 ±0.027),and they began to increase to 0.836±0.014 at 5 d and decrease to 0.674±0.013 at 7 d.Conclusions The simulated weightlessness has remarkable effect on the expressions of Hsp70 protein and mRNA in rat's pancreas,and the expressions are up-regulated in the early phase and returns to normal level in the late phase. Key words: Weightlessness simulated ; Pancreas ; HSP70 heat-shock proteins ; Rat