Correlation Between Sex-difference Of Depression And HPA Axis Function In Rat Model

Objective:To investigate the relation of rat sex-difference with depressivebehaviors to brain derived neurotrophic factor and monoamine oxidaseB expression as well as hypothalamic-pituitary-adrenal axis function.Methods:1. Sixty SD rats (30for male and female each) were randomlydivided into female control group(CF), male control group(CM), femalemodel group(SF), and female model group(SM). Chronic unpredictedmild stress（CUMS）with solitary condition was taken to establish ratdepression model.2. Elevated plus maze(EPM) and sucrose preference tests wereused to evaluate depressive behaviors.3. Activities of SOD，CAT and level of MDA，CORT in serumwere measured by biochemistry, radio-immunity. 4. Real-time PCR, and western blot were used to determinemRNA and protein expressions of hippocampus and cortex BDNF, aswell as hypothalamus CRF and cortex MAO-B, respectively.5. HE staining was used to observe the pathological change ofhippocampus slices by microscope.Results:1. Compared with corresponding control, sucrose consumptionand the frequencyfor SF and SM rats entering the open arms, anddownwards-exploring, and time staying in open arms significantlydecreased； serum CORT， MDA levels, and mRNA and proteinexpression of hypothalamus CRF and MAO-B significantly increasedwith obviously decreasing mRNA and protein expression ofhippocampus BDNF and serum SOD，CAT activities.2. Sucrose consumption and frequency for SM entering the openand closed arms, head-dipping and rearing, as well as time staying incentral place significantly decreased with longer time staying in closedarm in comparison with SF.3. There existed obvious sex difference of both serum CORT, MDAlevel and expression of hippocampus or cortex BDNF and hypothalamusCRF between CF and CM, as well as SF and SM, which of male waslower than female. Conclusions:Sex-specific difference of anxiety-depression-like behaviors of ratsinduced by CUMS is at least partly associated withoxidative/anti-oxidative stress balance and HPA axis function as well asBDNF，MAO-B expression from male and female.