Protective effect of morphine-baclofen co-administration on oxidative stress in the dorsal hippocampus in an experimental model of morphine-induced polycystic ovary in rats

The aim of this study was to evaluate the protective effect of baclofen, a GABAB agonist, against oxidative stress in the dorsal hippocampus (dH) of rats modeled as polycystic ovary (PCO) by morphine. Sixty-six female Wistar rats in the diestrus phase were randomly divided into 11 groups (n=6): the control group received only saline (1 mL/kg), the next two groups were treated with morphine (5 mg/kg, i.p.) once or twice, respectively. Six groups were treated with baclofen alone (10, 20 and 30 mg/kg) or baclofen dose as before morphine injection. The other two groups received morphine in two different ways: one was injected morphine (0.4 μg/rat), intra-VMH, and the last group that underwent gonadectomy received morphine (5 mg/kg) i.p. after recovery. Twenty-four h after treatment, blood samples were taken from rats’ hearts under deep anesthesia for serological studies. Hippocampal specimens were then isolated on ice for histological, immunohistochemical as well as oxidative stress factors (GPX, MDA, SOD, and CAT) evaluations. Estrogen and glucocorticoid receptor levels expressed in dH tissue were also examined. The ovaries and uterus were also biometrically examined. The results were analyzed using analysis of variance (α=0.05). Ovarian follicular cysts were more common in the morphine-receiving groups than in the control group. But the gonads improved with baclofen pretreatment. Oxidative factors showed high levels in the hippocampus of morphine-treated groups that correlated with low estrogen receptors at dH. Morphine causes both PCO and oxidative stress at dH, but the use of baclofen with morphine may protect them all.