Assessment of biochemical markers of bone turnover following chronic alcohol consumption in acyclic mice

Abstract

Chronic moderate alcohol consumption has been implicated in promoting bone health in acyclic (postmenopausal) women via increasing bone mineral density. To our knowledge, no studies investigated the potential effects of ethanol on the bone-specific markers osteocalcin and RANKL which are important in regulating osteoblast - osteoclast activity and bone metabolism. Therefore, the aim of the study was to look into RANKL expression in serum and RANKL and osteocalcin expression in the femoral neck following chronic alcohol consumption of 12% v/v ethanol in water in acyclic C57BL/6 mice. Female C57BL/6 mice, 12 - 13 months old, were housed under 12:12 L/D cycle (lights on at 0700) and given rodent chow ad libitum. After a week of adaptation to housing conditions, animals were divided into 2 groups: 1) a control group (C, N = 5) which was maintained on tap water and 2) an experimental group (E, N = 7) which received ethanol in the drinking water (12% v/v) for either 47 or 61 days (E1 and E2, respectively). Serum RANKL concentration, femur biomass, and OCN and RANKL immunoreactivity in the femur neck were assessed. Chronic alcohol consumption for about 10 weeks did not result in a significant change or keep as is resulted in an increase in serum RANKL concentration and a decrease in femur biomass in experimental animals as compared to control. In bone tissue, OCN immunoreactivity was similar in both control and experimental groups and did not vary between anterior and posterior sections, although it was weaker in experimental tissues. There was a differential regional distribution of RANKL immunoreactive osteoblasts in posterior sections of control tissues, primarily confined to the superior neck region, whereas protein immunoreactivity was weaker in more anterior sections. Experimental tissues, in contrast, showed no detectable RANKL immunoreactive osteoblasts along the anteroposterior axis.The present findings suggest that chronic administration of ethanol may possibly improve bone mineral density via pathways involving bone resorption, rather than formation processes. Understanding the potential positive role of ethanol on bone mineralization can have important health implications on improving the quality of life in middle-aged females.