PROTECTIVE ROLE OF MELATONIN AND TAURINE AGAINST TOXICITY INDUCED BY CAFFEINE IN BRAIN BY ABROGATION OF OXIDATIVE STRESS, DECREASE APOPTOSIS, AND ALTERS CEREBRAL MONOAMINE NEUROTRANSMITTERS IN MALE ALBINO RATS

The current study aimed to investigate the protective effects of taurine and melatonin against caffeine-induced brain damage in rats. 36 male albino rats were divided into 6 groups: Group I: control, group II: Rats received 20 mg/kg melatonin for 28 days. Group III: Rats received 50 mg/kg taurine dissolved in distilled water daily for 28 days. Group IV: Rats received 50 mg/kg caffeine dissolved in distilled water for 28 days. Group V: Rats received melatonin as described in group II in concomitant with caffeine, as described in group IV. Group VI: Rats received taurine as described in group III in concomitant with caffeine, as described in group IV. Caffeine-induced rats showed significantly increased brain lipid peroxidation, Superoxide dismutase (SOD) and reduced glutathione (GSH) content were significantly decreased. Monoamine neurotransmitters, gene and protein expression levels of p53 and Bax were significantly increased in the brain of caffeine-induced rats. In contrast, caffeine administration down-regulated Bcl-2 both gene and protein expression in the brain of rats. DNA damage were detected in caffeine treated group compared with control. Gene and protein expression levels of p53 and Bax were significantly decreased in the brain of taurine and melatonin administrated groups. Taurine and melatonin significantly decreased MDA and DNA damage, levels of dopamine and norepinephrine, and enhanced activity of the antioxidant enzymes in the brain of rats. In conclusion, taurine and melatonin can impact caffeine-induced oxidative stress and apoptosis through their antioxidant activity.