Fracture healing and bone mass in rats fed on liquid diet containing ethanol

Background: Studies in animal models for alcohol abuse have suggested that ethanol inhibits bone growth, decreases bone formation, and increases fracture risk. Methods: Experimental tibia fracture healing in rats fed a liquid diet containing 7.2% ethanol for 8 weeks was investigated with histological and osteodensitometric studies with respect to the control group. After 4 weeks of vitamin A- and sucrose-enriched milk containing 7.2% ethanol feeding, we created closed tibia fractures, which were then fixed with intramedullary nails, in 10 rats. After a follow-up time of 4 weeks, the rats were killed for examination. The same procedure was performed in another 10 rats, which were fed on the same diet (isocaloric modified liquid diet) but without ethanol and used as the control group. A histological scoring system was developed for fracture healing. Results: Histological evaluation of fracture region revealed an average fracture healing score of 1.9 in the ethanol-fed group versus 2.6 in the control group (p = 0.014). In the test group, dual-energy x-ray absorptiometry measurements in the fracture region showed a mean bone mineral density of 0.11 +/- 0.03 g/cm(2), whereas it was 0.130 +/- 0.051 g/cm(2) in the control group (p = 0.000). The mean bone mineral content in the fracture region was 0.103 +/- 0.08 g/cm(3) in the test group versus 0.128 +/- 0.06 g/cm(3) in the control group (p = 0.000). A significant correlation was found among histological scores, bone mineral density (r = 0.64, p = 0.04), and bone mineral content (r = 0,63, p = 0.04). Conclusions: This study showed that rats fed on a diet mixed with ethanol have a histologically delayed fracture healing associated with decreased bone density and mineral content. Besides the negative effects of ethanol on bone metabolism, it also interferes with the fracture-healing process.