Light and electron microscopic study on the possible protective effect of pomegranate peel extract on the pituitary- thyroid axis exposed to monosodium glutamate in adult male albino rats

Abstract

Background: Monosodium glutamate is one of our new high-tech food additives. Nowadays, use of natural antioxidant as pomegranate peel extract has become an attractive therapeutic strategy for reducing the risk of disease.Aim of work: this study was designed to assess the effects of MSG on the pituitary thyroid axis and the possible protective role of pomegranate peel extract.Material & methods: Forty adult male albino rats were divided into three groups. Group I: (control) that was subdivided into; subgroups I A & I B . Group II (MSG treated) received MSG at a dose of (6mg/g/day). Group III (MSG & Pomegranate peel treated) received MSG & PPE as same dose as subgroup I B and group II. At the end of the experiment, pituitary and thyroid glands were dissected out and processed for biochemical, histological, immune-histochemical, and electron microscopic studies. Results: MSG caused thyroid follicles distortion and degeneration. Follicular cells possessed vacuolated cytoplasm, and pyknotic nuclei. Decreased colloids & inflammatory infiltrates were detected. By E/M, follicular cells showed dilated RER cisternae, degenerated mitochondria, & depleted microvilli. While basophils of pituitary gland appeared degenerated with vacuolated cytoplasm. By E/M, thyrotrophes showed dilated RER cisternae, dilated Golgi apparatus, and degenerated mitochondria. There was a highly significant decrease (P value˂0.001) in the mean serum level of T3, T4 and TSH in Group II) as compared with group I. While group III showed a highly significant increase (P value˂0.001) in the same parameter as compared with group II. The administration of PPE induced improvements of these changes.Conclusion: This work demonstrated that pomegranate peel extract improves the histological & biochemical changes induced by MSG on the pituitary thyroid axis.Key words: monosodium glutamate, pituitary thyroid axis, pomegranate peel extract.