ABSTRACT
Objective To investigate the effects of proanthocyanidins on depressant-like behaviors and the structure of adrenal gland in chronic unpredictable mild stress (CUMS) rats. Methods Rats were randomly divided into 6 groups:control group, stressed group (CUMS + vehicle), three treatment groups (CUMS + proanthocyanidins 25,50,100 mg·kg-1,respectively) ,and imipramine group (CUMS + imipramine 10 mg·kg-1). Used the CUMS model in rats to investigate the effects of chronic oral administration (21 days) of proanthocyanidins and imipramine (ip) on the open-field;and forced swimming and sucrose consumption tests and the ratio of adrenal gland/body weight,and its thickness were examined by HE stain. Results Compared with control group, rats subjected to CUMS exhibited increased ratio of adrenal gland /body weight ( P < 0. 01), less sucrose consumption( P<0.01) and inhibited in the open-field test( P<0.01) as well as more despair time in the forced swimming test( P<0.01). While compared with stressed group,treatments with proanthocyanidins (25,50,100 mg·kg-1, po ,21 days) could significantly improve the activities in open-field test ((39.6±3.4) vs (49±4.5), (52.6±3.7),(54.1±1.8) ;all P<0.01) and sucrose consumption( (5.8±2.5)ml vs (8.1±3.3)ml,(8.5±4.1) ml, (9.2±2.6) ml; P < 0.05, P < 0.05, P < 0.01 respectively); Meanwhile, it could reduce the duration time in forced swimming test significantly( (103.5±10.2)s vs (83.7±8.8)s,(75.8±5.9)s,(67.2±6.5)s; all P<0.01) as well as thickness of the adrenal gland(P<0.05, P<0.01).Conclusions This study suggests that the proanthocyanidins (25,50,100 mg·kg-1) has an antidepressant-like effects in CUMS rats. The antidepressant actions of proanthocyanidins, in some degrees, may be related with the regulation of the adrenal gland's structure.