Effect of Hormone Replacement Therapy on Cognitive and Behavioral Pattern on Lead Induced Neurodegeneration in Ovariectomized Rats

ABSTRACT Menopause in women is associated with decline in estrogen (E) and progesterone (P), leading to cognitive function and exploratory behavior. Lead (Pb) exposure worsens cognition, potentially leading to neurodegenerative diseases. Estrogen plays a crucial role in regulating cognitive function and memory processes, with its effects on synaptogenesis in the hippocampus being particularly significant. This study aimed to evaluate the effects of hormone replacement therapy (HRT) on cognitive and behavioral patterns in Pb-induced ovariectomized rats. Sixty female Wistar rats (200-250 g) were grouped into six (n=10);1: sham; 2: Ovariectomy (ovx); 3: Pb; 4: ovx+Pb; 5: ovx+HRT; 6: ovx+Pb+HRT. Group 3, 4 and 6 received 20 mg/kg Pb acetate solution, while 5 and 6 received 0.5 μg/kg E and P combined daily for 28 days via galvage. All the groups received vehicles (0.2 mls of olive oil and distilled H2O via galvage for 28 days). Behavioral studies were carried out on the 28 day. Data were expressed as mean with ANOVA using Graphpad prism and multiple comparison by Tukey post-hoc test. Statistical significance was set at P< 0.05. There was a statistical significant reduction in the neurobehavioral indices (Y-maze, elevated plus maze and open field test) in pb, ovx only, ovx + Pb when compared to sham and all these indices were significantly raised in the groups that received HRT (ovx + HT, Ovx + Pb + HT). In conclusion, this showed that hormone replacement therapy (HRT) improved cognitive and behavioral patterns in lead-exposed ovariectomized rats.