Melatonin attenuates ovarian injury concomitantly with alterations in SMAD7 protein expression and related microRNAs in a rat model of adnexal torsion-detorsion.

This study aimed to investigate the histopathological and molecular effects of melatonin on ovarian follicle reserve, SMAD7 immunolocalization, and SMAD7-related miRNAs (miR-182, miR-21, miR-92) in a rat model of adnexal torsion-detorsion (TD). Twenty-eight adult female rats were divided into four groups (n = 7). Group 1 (Control) underwent no procedure, while Group 2 (TD) received 2-h torsion followed by 2-h detorsion. Group 3 (TD + Solvent) and Group 4 (TD + Melatonin) were administered ethanol or melatonin intraperitoneally 15 min before detorsion, respectively. Ovarian tissues and serum samples were analyzed histopathologically, biochemically, and molecularly. In Group 2, follicular atrophy, cystic degeneration, and increased connective tissue and vascular congestion were observed, whereas Group 4 exhibited reduced cystic follicles and preserved follicular architecture. SMAD7 expression decreased in Group 2 and increased in Group 4. Although not reaching statistical significance, TOS tended to increase and TAS tended to decrease in Group 2, whereas the opposite trend was observed in Group 4. miR-21, miR-182, and miR-92 expression levels significantly increased in Groups 2 and 3 compared with the control but remained comparable to the control in Group 4. These findings indicate that melatonin contributes to the attenuation of acute structural damage in ovarian follicles, modulation of oxidative stress, and regulation of SMAD7-related miRNAs in the TD model. Melatonin may play a protective role against torsion-detorsion-induced acute ovarian injury, showing a strong association with the modulation of oxidative stress, SMAD7 immunoreactivity, and specific miRNA expression levels.