Effects of melatonin on the teratogenicity of alcohol in albino rat

ABSTRACT

Teratogenicity of alcohol has been widely studied in humans and laboratory animals. Alcohol seems to produce its deleterious effects through its capability to release harmful free radicals. The aim of the present study was to determine the potential role of exogenous melatonin as a free radical scavenger [antioxidant] against the teratogenicity of alcohol. Twenty four pregnant albino rats were randomly divided into four equal groups control, alcohol, melatonin and melatonin-alcohol. Treatment was given intragastrically daily from day 6 through day 12 of gestation. Twenty days full term rat fetuses were then collected. Two thirds of the fetuses were fixed in Bouin's solution for external and visceral examinations. Skeletons of the remaining third of the fetuses were stained with alizarin red for their evaluation. The present study revealed the teratogenicity of alcohol even in its mild dose of 15 ml/kg BW [ethanol, 25% v/v]. In the experimental rats, it increased the rate of resorptions and delayed the fetal growth. It also affected the ossification of the skeletal system and produced different congenital abnormalities. Exogenous melatonin given in this study in a dose of 9 mg/kg BW did not affect significantly the fetal growth and development and did not produce any congenital abnormalities. However, all developmental parameters assessed in this study were found to be normal in the melatonin-alcohol group when compared to the control group. Also, no congenital abnormalities were detected. The results obtained from this study indicate that melatonin probably acts as a negative coteratogen as it counteracts the teratogenic effects of alcohol. The present results also support those reported by previous workers which indicated the role of free radicals in mediating the teratogenicity of alcohol. According to the present findings, it is suggested that any substance known to release free radicals should be prohibited during pregnancy. If it is necessary, it should be combined with a potent antioxidant, to avoid its teratogenic effects