The Effects of Acute and Chronic Immobilization Stress and Aloe vera Extract on Serum Levels of TSH, T3 and T4 in Male Rats

Stress has different effects on the body and endocrine system. The main aim of this study is to determine the effects of immobilization stress and Aloe vera extract on levels of TSH, T3 or T4 in male rats. In this experimental study, 90 male Wistar rats were randomly divided into 9 groups of control, receiving normal saline, receiving Aloe vera extract, acutely immobilized (8 h/day immobilization for 8 days), chronically immobilized (2 h/day immobilization for 21 days) acutely immobilized receiving Aloe vera extract, chronically immobilized receiving Aloe vera extract, acutely immobilized receiving normal saline and chronically immobilized receiving normal saline (n = 10). Blood samples were collected using cardiac puncture method and hormone levels were measured by electrochemiluminescence (ECL) method. Data were statistically analyzed and compared among groups using ANOVA. Results showed that levels of T3 and T4 were significantly increased in rats enduring acute immobilization stress compared with animals in control group (P = 0.001). Serum T3 and T4 were significantly decreased in Aloe vera receiving rats compared with control group (P < 0.05 or P < 0.01, respectively). Level of T3 was significantly decreased in acutely immobilized rats receiving Aloe vera compared with control group (P = 0.001). Level of T3 and T4 levels were significantly decreased in chronically immobilized rats receiving Aloe vera compared with control group (P < 0.05). The findings show that acute immobilization enhances levels of T3, T4 and TSH and the use of Aloe vera extract can prevent this kind of increase.