FETAL ALCOHOL EFFECTS ON THE POSTNATAL-DEVELOPMENT OF THE RAT MYOCARDIUM - AN ULTRASTRUCTURAL AND MORPHOMETRIC ANALYSIS

Heart disease is an entity frequently seen in the fetal alcohol syndro me. This paper describes the effect of in utero ethanol exposure on th e postnatal ultrastructural development of rat cardiac muscle. To dete rmine this time-pregnant Sprague-Dawley rats were fed either a nutriti onally balanced protein- and vitamin-enriched liquid ethanol diet (wit h 36% of the calories derived from ethanol) or a liquid diet with malt ose-dextrins isocalorically substituted for ethanol. The latter group was designated the pairfed control group. At birth, pups of both the g roups were surrogate-fostered by normal dams. Body weights and crown-r ump lengths were significantly less in the rat pups exposed to ethanol in utero at 21 days postnatal. Ultrastructural analysis of the cardia c muscle was performed at 7, 14, and 21 days postnatal in ethanol and pairfed groups. Several morphological features of myocyte damage were observed in ethanol-exposed pups, predominantly at 7 days postnatal, w ith nearly total absence of myocyte damage by 21 days postnatal. The m ost outstanding changes were observed in the myofibrils, which showed dysplastic changes at 7 days postnatal, a delay in M-band structural d evelopment at 14 days postnatal, and a significantly smaller myofibril volume density per tissue volume at 21 days postnatal in the ethanol rat pups compared to the pairfed controls. (C) 1994 Academic Press, In c.