Effect of ethanol on bone mineral density of rats evaluated by dual-photon X-ray absorptiometry

Abuse of alcohol may derange bone metabolism and cause osteoporosis. Due to confounding factors associated with alcohol abuse, e.g., dietary deficiencies and liver damage, a study using an animal model is preferable to examine whether alcohol itself actually reduces bone density. We evaluated the effect of alcohol intake on bone in rats by dual-energy X-ray absorptiometry. Six-week-old male (n = 16) and female (n = 16) Wister rats were divided into two groups. Sixteen alcohol-exposed rats (8 male and 8 female) were fed Lieber's liquid diet and 16 control rats (8 male and 8 female) were fed a control liquid diet. The bone mineral density (BMD) and bone mineral content (BMC) of the right femur were measured before and after experimental feeding under anesthesia. The BMD of lumbar spine (L2-L4) of sacrificed rats was measured. For male rats, BMD and BMC decreased significantly in the alcohol group (P = 0.0132 and 0.0133, respectively) but did not decrease in control group. For female rats, BMD and BMC decreased significantly in the alcohol group (P = 0.0012 and <0.0001, respectively) but did not decrease in the control group. For male rats, the mean ratio of BMD after experimental feeding divided by BMD before experimental feeding was significantly lower in the alcohol group than in the control group (P = 0.0031). For female rats, the mean ratio of BMD after experimental feeding divided by BMD before experimental feeding was also lower in the alcohol group than in the control group (P = 0.0002). For male rats, the mean BMD of L2-L4 after experimental feeding was significantly lower in the alcohol group than in the control group (P = 0.0210). For female rats, the mean BMD of L2-L4 after experimental feeding was also significantly lower in the alcohol group than in the control group (P = 0.0006). These results indicate that alcohol intake decreased the BMD of rats in both spongy and cortical bone, and that the reduction of BMD was greater in female rats than in male rats.