Chronic and intermittent exposure to alcohol vapors: a new model of alcohol-induced osteopenia in the rat.

BACKGROUND: Different models are used to study the effects of chronic alcohol consumption on bone tissue in the rat. However, the current models take several months to show indices of osteopenia as observed in chronic drinkers. Numerous studies have supported that chronic and intermittent exposure to ethanol vapors has predictive validity as a model of alcohol dependence in humans. However, this model has never been applied to bone research to study its effects on the parameters that define osteopenia. This was the goal of this study in the rat. METHODS: Male Wistar rats were exposed to ethanol vapor inhalation (n = 6) or air (controls, n = 6). Animals were exposed to chronic (11 weeks) and intermittent (14 hours a day) ethanol vapor reaching stable blood alcohol levels (BALs; 150 to 250 mg/dl) at the end of the third week of inhalation. After the sacrifice, right and left femur and tibia were dissected free of fat and connective tissue and bone mineral density (BMD) was assessed by dual X-ray absorptiometry. The microarchitecture of the femur was studied using microcomputed tomography. RESULTS: The BMD of the left and right femurs and the left tibia was lower in the ethanol group compared with the control group. The bone volume fraction (BV/TV) and the bone surface density (BS/TV) were lower in the ethanol group compared with control animals. The trabecular number (Tb.N) was lower in the ethanol group while the trabecular spacing was higher. CONCLUSIONS: The decrease in the BMD, BV/TV, and Tb.N is in the same range as what is observed in human drinkers and what is reported with other animal alcohol models (Lieber-DeCarli liquid diet, ethanol in the tap water). Therefore, this model could be useful to study the effects of chronic alcohol consumption in the bone research field and has the advantage of controlling easily targeted BALs.