Alcohol consumption by young actively growing rats: a study of cortical bone histomorphometry and mechanical properties.

Alcohol consumption by young actively growing rats has been previously demonstrated to decrease cortical and cancellous bone density, to reduce trabecular bone volume, and to inhibit bone growth at the epiphyseal growth plate. This study addresses the action of alcohol on cortical bone growth using histomorphometric techniques and on mechanical properties by three-point bending. Four-week-old, female Sprague-Dawley rats were divided into three groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin-substituted calories were supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Femora were removed for analysis after 2, 4, 6, or 8 weeks on the diets. Cortical bone area, bone formation rates, and mineral apposition rates were reduced in the alcohol-fed animals. Bone stiffness, strength, and energy absorbed to fracture were significantly lower in the alcohol-fed animals. This distinctive alcohol effect was revealed to be caused by lower quality bone tissue as reflected by lower elastic moduli and yield strengths.