الفهرس 
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Abstract
Although monosodium glutamate (MSG) is one of the most widely used flavor enhancersthroughout the world and being produced in large quantitiesthroughout the world,there are controversies over safety of it. MSG has reported to induce oxidative stress and toxicity.Accordingly, interest has recently grown in the role and usage of natural antioxidants as means to prevent oxidative damage induced by MSG.
The present study aims to explore the protective daily administration effects of quercetin,phenolic antioxidant, at a dose of 14 mg/ Kg b. wt. for four weeksagainst the side effects induced by oral MSGadministration at a dose of 15 mg/ kg b.wt. on liver, testis and ovary ofmale and female rats on biochemical, histological and ultrastructural levels.
For testing the protective effects of QU on MSG-induced toxicity, 60male and female albino rats (Rattus norvigicus) were divided into five groups (six rats / each) designated as follow: group I administered distilled water, in a respective volume to MSG. group II administered distilled corn oil in a volume relevant to quercetin. group III wastaken daily 14 mg/ Kg b. wt. of quercetin orally. group IV was orallygivenMSG at a dose of 15 mg/ Kg b. wt. daily for four weeks group V was administrated MSG simultaneously with quercetin daily for four weeks.
At the end of the experimental period, the animals of all groups were sacrificed under mild diethyl ether anesthesia and blood samples and tissues were collected.The clear non haemolysed supernatant serum was quickly removed for analysis of various biochemical parameters. Fixed tissue specimens of liver, ovary and testis were examined for the histological lesions demonstration. Another part of the selected tissues was homogenized in 0.9% NaCl (10% w/v) for the measurement of oxidative stress markers.
The obtained data of the above mentioned investigations can be summarized in the following:
The animals received MSG alone showed histological, ultrastructure and biochemical changes.
MSG administration induced a significant increase in body weight percentage change.
Histopathological assessments of the liver, after administration with MSG, revealedblood congestion, inflammatory cell with infiltrations, bile duct proliferation, cytoplasmic vacuolation, pyknosis and karyolysis. Electron microscope examination recordedan accumulation of collagen fibersand lipid droplets in some area, cytoplasmic degeneration, swollen mitochondria,dilation of endoplasmic reticulumandthe bile duct without detached microvilli andKupffer cell with abnormal size nucleus, condensed chromatin andlipid droplet accumulation.
Microscopic examination of the testis of rats treated with MSG showedirregular and disorganized seminiferous tubules, detachment of spermatocytes, sloughing of cell into lumen, pyknotic nuclei, inflammation, vacuolation and congestion. Ultrastructural examination showed autolysis, fragmented chromatin, vacuolation of spermatogonia, sertoli cells, primary spermatocytesand leydig cell, active lysosomes, degeneration of spermatids and decrease in number of sperms in lumen of seminiferous tubules.
Results of microscopic investigations in ovary revealed atretic follicles, cytoplasmic vacuolation, pyknotic nuclei, congestion and dilation of blood vessels,hyalinization, fibrotic changes in stromal cell, hyperplasia in corpus luteal cells occupying most of the ovary and degenerated corpus luteum. Ultrastructural examination of the ovary sections showednoticeable degenerative changes occurred in the organelles of oocytes and granulosa cells. Granuolsa cells with shrunken nucleus,vacuolation and lipid droplet and presence of lysosomes in oocyte were also observed.
MSG-intoxicated male rats showed significant increase in activity of liver function enzymes (ALTand AST) and significant decrease in serum testosterone and estrogen levels.Moreover, MSG recorded more pronounced effect on testosterone level than estrogen. However, there was no significant difference in activity of ALT and AST between male and female rats treated with MSG.
MSG-intoxicated rats showed a significant increase in lipid peroxidation level accompanied with significant decrease in content of GSH and theactivity GSH-Px and SOD in liver, testis and ovary. However, MSG showed more pronounced effect on the activity of hepatic GSH-Px and hepatic GSH content in male than female rats,there was no significant difference between male and female rats treated with MSG concerning enzymatic and non-enzymatic antioxidant parameters in ovary and testis.
In liver, testis and ovarymost recorded histological lesionsand ultrastructure changes resulted from MSG administration were nearly ameliorated after the treatmentwith quercetin.This amelioration is accompanied by significant decrease in the level of lipid peroxidation, activity of liver functions (ALT and AST) and significantincrease in activity of SOD and GSH-Px,content ofGSHand hormonal content of (testosterone and estrogen).