Study on the Protective Effect of Methylene Blue Against the Neurological Toxicity of Carbon Monoxide in Adult Female Albino Rats

The present study aimed to investigate the protective effect of methylene blue (MB) administration (1 mg/kg i.p/ day) for 30 days in cerebral cortex and brain stem under carbon monoxide (CO) intoxication (1% for 4 minutes/ day) in female adult albino rats. Animals were divided into four groups. Control group that received stock diet, MB group that received methylene blue, CO group that inhaled CO for 4 minutes in a closed chamber and MB+CO group, where the animals were administered MB then inhaled CO. Superoxide dismutase (SOD), reduced glutathione (GSH), malondialdhyde (MDA) as biochemical markers of redox homeostasis and adenosine triph-osphate (ATP) contents were measured in brain stem and cerebral cortex, additionally levels of norepinephrine, dopamine and serotonin were measured. CO-treated animals caused an increase in MDA a com-bined with decrease in GSH and SOD which may be due to its oxidative stress. Also CO caused decrease in ATP, DA and increase in NE and 5- HT which may be due to its effect on mitochondrial enzymatic chain which led to decrease in ATP content. The decrease in DA level may be due to decrease in up take mechanism which depend on ATP. On the other hand the increase in NE may be due to its effect on CGMP path way which causing hypotension and increase up take of NE. The pretreatment of CO with MB ameliorate the toxic effect of CO by improving energy production in oxidative phosphorylation process and scavenging the free radicals.