Histomorphological Assessment of Adrenal Glands in Wistar Rats Following Myricetin Treatment Against MNU-Induced Oxidative Stress

Aim: This study aimed to investigate the protective effects of myricetin against oxidative stress induced by N-Methyl-N-Nitrosourea (MNU) in Wistar rats, emphasizing its impact on adrenal gland histomorphology and antioxidant enzyme activities.

Study Design: The study utilized a randomized controlled trial design with seven groups: normal control (Group A), MNU (Group B), MNU + Casodex (Group C), 100mg myricetin (Group D) and varying doses of myricetin (Groups E-F) administered to rats that had been subjected to MNU-induced oxidative stress.

Place and Duration of Study: The experiment was conducted at the University of Calabar between February 2024 and October 2024.

Method: A total of 42 male Wistar rats were used in this study. Oxidative stress was induced in the experimental groups through intraperitoneal administration of MNU (50 mg/kg). Following MNU exposure, varying doses of myricetin (75 mg/kg, 150 mg/kg, and 300 mg/kg) were administered orally for three weeks. Biochemical assays measured antioxidant enzyme activities, namely Superoxide Dismutase (SOD), Catalase (CAT), and Glutathione Peroxidase (GPx). Histological evaluations of adrenal glands were performed using hematoxylin and eosin (H&E) staining.

Results: Findings indicated that antioxidant and oxidative stress markers (superoxide dismutase, catalase, malondialdyhide) was significantly higher (p<0.05) after induction while (glutathione) also showed slight significant increase in the induction group when compared to normal control group. Results after treatment with myricetin showed significant reduction in oxidative stress markers (superoxide dismutase, catalase). Malondialdyhide showed statistically (p<0.05) significant difference in groups D & E. However, there was no statistically significant difference in glutathione level across the groups following treatment with doses of myricetin, but the group induced with 50mg of nitrosourea only showed a slightly increase in the mean expression of glutathione. Histopathological analysis revealed that myricetin treatment preserved the structural integrity of the adrenal glands, showcasing a dose-dependent restoration of normal architecture and improved vascular arrangement, particularly in the highest treatment group.

Conclusion: This study suggests that myricetin has promising therapeutic potential for protecting adrenal gland integrity from MNU-induced oxidative stress. The observed improvements in antioxidant enzyme activities and histological preservation underscore myricetin's role as a natural product for alleviating oxidative damage in endocrine dysfunction. These findings support the integration of myricetin into treatment strategies for conditions associated with oxidative stress, highlighting the importance of natural compounds in modern medicine.