Effects of voluntary wheel running exercise on depressive-like behavior and circadian rhythmic alterations of neuroendocrine induced by chronic unpredictable mild stress in rats / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effect of 8-week middle intensity voluntary wheeling exercise on the de-pressive-like behavior and the circadian rhythmic alterations of plasma hormone and peptide induced by chronic unpredicta -ble mild stress (CUMS) in rats.METHODS: Male Sprague-Dawley rats (n =90) were randomly divided into model group, model+exercise group and control group .Rats in model+exercise group received 8-week voluntary wheel running exercise plus CUMS procedure during the last 3 weeks at the same time .Exploratory locomotor activity was assessed by open field test, the anxiety-like behavior was measured by elevated plus-maze test, and lack of pleasure was detected by su-crose preference test.Blood samples were collected at each of 6 time points (ZT1, 5, 9, 13, 17 and 21 on the 2nd day af-ter behavior testing ) .Plasma concentrations of corticosterone ( CORT) , melatonin ( MT) and vasoactive intestinal peptide ( VIP) were detected by ELISA .The plasma concentration of adrenocorticotropic hormone ( ACTH) was measured by ra-dioimmunoassay .The circadian rhythm changes of serum CORT , MT, VIP and ACTH concentrations in each group were compared by cosinor analysis .RESULTS:Compared with control group , locomotor activity , weight gain and sucrose con-sumption in model group were significantly reduced ( P<0.01 ) .The values of the percentage of open-arm time ( OT%) and open arm entries ( OE%) were obviously lower in model group than those in control group ( P<0.01 ) .Eight-week voluntary wheel running exercise may improve the above depression behavior caused by CUMS .The rats in model group showed an obvious disorder in circadian rhythm of plasma ACTH and CORT , including phase advance and decrease in am-plitude.There also showed a markedly blunted circadian rhythm and decreased level of plasma MT in model rats compared to control rats.VIP expression was significantly higher than that in control group with 24 h rhythm, but the amplitude was significantly lower than that in control group , peak phase also delayed for 6 h.Eight-week exercise significantly ameliorated the abnormal expression and the disturbance secretion rhythm of ACTH , CORT, MT and VIP in plasma .CONCLUSION:Eight-week voluntary wheeling exercise ameliorates CUMS-induced depressive-like behaviors probably by rescuing the dis-turbed circadian rhythms and abnormal secretion of these neuroendocrine factors .