Synergistic Protective Effects of L-Carnitine and Sodium Thiosulfate Against Monosodium Glutamate-Induced Testicular Toxicity in Male Rats

• Hussain M. Jalil1 and Areej GH. Al-Charak1*.

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Monosodium glutamate (MSG) is a common food additive to improve taste with the potential of health-damaging effects, specifically on reproductive capacity. MSG is known to produce oxidative stress, which causes the decrease of steroid hormone synthesis, ultimately interfering with male reproductive organs function. This study aims to investigate the protective effects of carnitine and sodium thiosulfate as antioxidant monotherapy and their combination in protecting from MSG-induced testicular injury in male rats. A total of forty male Wistar rats were assigned to five groups of 8 [8/Group]. Group 1 (Control): received daily oral gavage of 1 mL distilled water; Group 2 (Positive control): monosodium glutamate at a dose of 1000 mg/kg bw, diluted in normal saline, delivered from orogastric tube once daily; Group 3: administered L-carnitine (100 mg/kg bw/day orally one hour prior to administration of MSG (1000 mg/kg bw/day); and group 4: received an intraperitoneal injection with sodium thiosulfate (400 mg/kg bw/day) one hour before the administration of MSG. Group 5: Monosodium Glutamate (1000 mg/kg bw/day) + L-carnitine (100 mg per kg bw each day) orally and intraperitoneally, sodium thiosulfate at a dose of 400 mg/kg/body mass /day. The experiment was conducted for 60 days. MSG exposure caused significant male reproductive toxicity, as evidenced by a decreased sperm count, motility, and morphology; this effect was accompanied with increased levels of malondialdehyde (MDA) but decreased superoxide dismutase (SOD). Individual administration of L-Carnitine (LC) and Sodium Thiosulfate (STS) alleviated these effects; however, the combinatory treatment manifested greater outcomes, leading to more significant amelioration in sperm quality and antioxidant capacity.

Conclusion: The present study shows that MSG administration leads to the development of a dose-response relationship for the impairment of testicular hormone regulation, sperm count, pathohistological changes, and biomarkers of oxidative stress in adult male Wistar rats. The results indicate that the combination treatment with antioxidants works as a synergistic protector against MSG-induced reproductive toxicity.

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