IS MONOSODIUM GLUTAMATE A CLASSIC INDUCER OF UTERINE FIBROID?

Abstract

Previous preclinical research used monosodium glutamate (MSG) to induce uterine fibroid growth in experimental rat models, using elevations in estrogen, progesterone, total protein and total cholesterol as yardstick. This, however, remains inconsistent and largely hypothetical with inconclusive uterine histopathological and radiological evidence. This study was aimed at assessing the clinical, biochemical, histological and radiological changes in the uterus of female Wistar rats after the administration of MSG. Twenty five Virgin female Wistar (142.50 ± 3.01 g; n = 5/group) rats in Groups 1, 2, 3, 4 and 5 were orally administered 1 ml of distilled water, same volume corresponding to 50, 100, 200 and 400 mg/kg body weight of MSG, respectively, once daily for 30 days. Comprehensive clinical, biochemical, histological and radiological imaging was determined. All the doses of MSG significantly (p < 0.05) increased body weight, uterine weight, uterine coefficient, prolactin, LH, FSH, aromatase, 17-β hydroxysteroid dehydrogenase, nitric oxide synthase, nitric oxide, alkaline phosphatase, alanine aminotransferase, vitamin C, creatinine, urea, alkaline phosphatase, 8-hydroxy, 2'deoxyguanosine and advanced oxidation protein product whereas it decreased (p < 0.05) estradiol, testosterone, gonadotropin releasing hormone, progesterone and aspartate aminotransferase. The total cholesterol, high density lipoprotein-cholesterol, low density lipoprotein cholesterol, total protein and calcium increased only at 100, 200 and 400 mg/kg body weight whereas triglycerides only decreased at 100, 200 and 400 mg/kg body weight. The MSG did not significantly (p >0.05) alter the levels of phospholipids and transforming growth factor-beta The MSG at 50 and 100 produced uteri . with well-defined outline, increase in uterine size, anterior-posterior diameter and uterine compartment diameter whilst the 200 and 400 mg/kg body weight induced uterine horn hyperplasia, loss of anatomical definition, unclear outlines, irregular mixed echo with increase in uterine volume. Histologically, the 50 and 100 mg/kg body weight of MSG increased cellularity with glandular degeneration of the uteri whilst the 200 and 400 mg/kg body weight produced stroma densely packed with diffused smooth muscle cells proliferation and absence of growth/mass/tumour. Although, changes in clinical, biochemical, histological and uterine ultrasound were induced by the MSG, the absence of growth or mass in the uterus of the animals is insufficient to drive induction of fibroid.