Monosodium glutamate (MSG) is a worldwide food flavour enhancer commonly used by the food industry. This feed additive may cause male infertility. Nigella sativa seeds (NSS) is a widely used in herbal medicine as it has many biological benefits and could provide a solution. This work was designed to investigate the histological effects of NSS on rats ingesting MSG. To achieve this aim, adult male albino rats (2- 3 months old) were randomly and equally assigned into three experimental groups. For a period of 21 days, control group received no treatment, MSG group received MSG as 30 g/kg feed, and MSG + NSS group received MSG as 30 g/kg feed and NSS as 30 g/kg feed. Seminal vesicle histopathology in MSG group showed mild seminal vesiculitis with degeneration of smooth muscle fibers in tunica muscularis. In addition, there was an increase in the amount of connective tissue and apoptotic cells count. Periodic Acid Schiff stain indicated irregular and interrupted epithelial basement membranes. Glutathione reductase (GR), superoxide dismutase 2 (SOD2), and caspase-3 immuno-expressions increased in MSG group. It was found that there was an increase in the number of apoptotic cells, intraepithelial lymphocytes and dendritic cells in MSG group. However, treatment with NSS ameliorated these disturbances. NSS mitigated MSG-induced seminal vesicle damage by its histoprotective, cytoprotective and anti-apoptotic activities.

KEYWORDS
Monosodium glutamate, Nigella sativa seeds, Seminal vesicle, Apoptotic cells, Seminal vesiculitis, Dendritic cells, Lymphocytes.