Effect of Treadmill Training on Ovarian Alterations in A Rat Model of Congenital Hypothyroidism

Thyroid hormones are essential for fetal development, and maternal hypothyroidism may cause reproductive abnormalities in offspring. Physical activity may provide therapeutic benefits. This study investigated the effects of treadmill training on gonadotropin levels, oxidative stress biomarkers, and ovarian histopathological changes in postpubertal rat offspring with congenital hypothyroidism.

In this experimental study, congenital hypothyroidism was induced by administering propylthiouracil in the drinking water of pregnant Wistar rats from gestational day 6 to postnatal day 28. Female offspring were subsequently assigned to four groups (n=7/group): control, control with treadmill training, hypothyroid, and hypothyroid with treadmill training. Rats underwent treadmill training for 4 weeks (5 days/week, 30 minutes/session), with running speed increasing from 2-4 m/minutes during the first 2 weeks to 2-8 m/minutes during the final 2 weeks. After the final training session, blood and ovarian tissues were collected. Serum thyroid hormones and gonadotropins were measured using ELISA kits. In ovarian tissue, follicles were assessed using H and E staining; malondialdehyde (MDA) and glutathione (GSH) levels were measured spectrophometrically, and superoxide dismutase (SOD) and catalase (CAT) activities were determined using commercial assay kits.

Hypothyroidism significantly reduced serum thyroid hormones and gonadotropins. It was associated with increased oxidative stress, characterized by elevated MDA levels, decreased GSH levels, and reduced SOD and CAT activities, accompanied by a significant reduction in the number of growing ovarian follicles. Treadmill training ameliorated ovarian alterations in hypothyroid offspring by attenuating oxidative stress and enhancing antioxidant defenses, indicated by a 29% reduction in MDA levels, a 47% increase in GSH levels, and 37% and 51% increases in SOD and CAT activities, respectively.

Congenital hypothyroidism disrupts hormonal balance, increases oxidative stress, and induces ovarian histological alterations. Treadmill training exerts protective effects, highlighting its potential as a non-pharmacological strategy that could mitigate reproductive complications associated with hypothyroidism.