# The Impact of Black Walnut (Juglans nigra) Oil on Male Wistar Rats Suffering from Methimazole-Induced Hypothyroidism

## TL;DR

This study examines how black walnut oil affects male rats with hypothyroidism caused by methimazole, focusing on oxidative stress and thyroid hormone levels.

## Contribution

The study explores the therapeutic potential of black walnut kernel oil in a rat model of methimazole-induced hypothyroidism.

## Key findings

- Black walnut kernel oil contains essential fatty acids, hydrocarbons, and phenolic compounds.
- The extract increased T4 levels in hypothyroid rats, but the change was not statistically significant.
- T3 levels were significantly decreased in the methimazole-treated group compared to the control.

## Abstract

Hypothyroidism is a major endocrine disorder characterized by the dysfunction of thyroid hormones.

This study aimed to investigate the potential therapeutic effects of an oily extract derived from black walnut (Juglans nigra) kernels on methimazole-induced hypothyroidism in adult Wistar rats.

In this experimental study, hypothyroidism was induced by the oral administration of methimazole at a single dose of 25 mg/kg body weight. In this research, 40 adult male rats were used in five groups of eight, all of which were administered orally. At the end of the experimental period, blood samples were collected from the hearts of animals for the evaluation of oxidative stress and thyroid function parameters. Serum malondialdehyde (MDA) and nitric oxide (NO) levels were assessed as markers of oxidative stress, while catalase (CAT) and superoxide dismutase (SOD) enzyme activities were measured as indicators of antioxidant defense. Thyroid hormone levels [triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH)] were determined using ELISA-based assay kits. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post-hoc test.

Black walnut kernel oil was found to contain essential fatty acids, various hydrocarbons, and phenolic compounds. Consequently, using treatment with black walnut kernel extract in hypothyroidism rats, the SOD and T4 levels were decreased in the methimazole-treated stress group in comparison with the control group (P > 0.05), while T3 and CAT levels were significantly decreased in the methimazole-treated stress group in comparison with the control group (P < 0.05). Furthermore, the TSH, Anti thyroid peroxidase (TPO), NO, and MDA levels were increased in the methimazole-treated stress group in comparison with the control group (P > 0.05).

Although the ethanolic extract of black walnut (J. nigra) led to an increase in T4 levels in hypothyroid rats, the change was not statistically significant, and T3 levels were significantly decreased. Therefore, the extract did not demonstrate a clear improvement in thyroid function.