Partial Protection by Dietary Antioxidants Against Ethanol‐Induced Osteopenia and Changes in Bone Morphology in Female Mice

Abstract

Background Chronic alcohol consumption leads to increased fracture risk and an elevated risk of osteoporosis by decreasing bone accrual through increasing osteoclast activity and decreasing osteoblast activity. We have shown that this mechanism involves the generation of reactive oxygen species (ROS) produced by NADPH oxidases (NOX). It was hypothesized that different dietary antioxidants, N-acetyl cysteine (NAC, 1.2mg/kg/d) and α-tocopherol (VitE, 60 mg/kg/d)) would be able to attenuate the NOX-mediated ROS effects on bone due to chronic alcohol intake. Methods To study the effects of these antioxidants, female mice received a Lieber DeCarli liquid diet containing ethanol (EtOH) with or without additional antioxidant for 8 weeks. Results Tibias displayed decreased cortical bone mineral density in both the EtOH and EtOH+antioxidant groups compared to pair-fed (PF) and PF+antioxidant groups (P<0.05). However, there was significant protection from trabecular bone loss in mice fed either antioxidant (P<0.05). MicroCT analysis demonstrated a significant decrease in bone volume (BV/TV) and trabecular number (Tb.N) (P<0.05), along with a significant increase in trabecular spacing (Tb.Sp) in the EtOH compared to PF (P<0.05). In contrast, the EtOH+NAC and EtOH+α-tocopherol did not statistically differ from their respective PF controls. Ex vivo histological sections of tibias were stained for nitrotyrosine, an indicator of intracellular damage by ROS, and tibias from mice fed EtOH exhibited significantly more staining than PF controls. EtOH treatment significantly increased the number of marrow adipocytes per mm as well as mRNA expression of aP2, an adipocyte marker in bone. Only NAC was able to reduce the number of marrow adipocytes to PF levels. EtOH fed mice exhibited reduced bone length (P<0.05) and had a reduced number of proliferating chondrocytes within the growth plate. NAC and Vitamin E prevented this (P<0.05). Conclusions These data show that alcohol’s pathological effects on bone extend beyond decreasing bone mass and suggest a partial protective effect of the dietary antioxidants NAC and α-tocopherol at these doses with regard to alcohol effects on bone turnover and bone morphology.

Reduced Serum Osteocalcin in High‐Risk Alcohol Using People Living With HIV Does Not Correlate With Systemic Oxidative Stress or Inflammation: Data From the New Orleans Alcohol Use in HIV Study

“…Our results did not show an increase in the inflammatory marker CRP in subjects with the highest PEth values. Our finding that alcohol consumption was positively associated with oxidative stress (via increased 4‐HNE) agrees with previously reported mechanisms of alcohol (Alund et al., ; Ronis et al., ). However, these changes were modest and not correlated with osteocalcin.…”

“…Our measures would not be able to detect bone‐localized oxidative stress, and this could be the underlying cause of the suppressed osteocalcin secretion by osteoblasts. Suppressed osteocalcin is consistent with NADPH oxidase‐dependent ROS production observed in bone from rodents exposed to EtOH in vivo, and in mesenchymal stem cells and osteoblasts exposed to EtOH in vitro (Alund et al., ; Chen et al., ; Watt et al., ).…”

“…Disruptions to calcium homeostasis have also been reported among people consuming hazardous levels of alcohol (Laitinen et al., ; Míguez et al., ). Mechanistically, animal models have demonstrated that alcohol‐induced oxidative stress in osteoblasts suppresses proosteoblastic signaling while increasing osteoclast differentiation to promote resorption (Chen et al., ; Mercer et al., ), and dietary antioxidants protect against ethanol (EtOH)‐induced bone loss (Alund et al., ; Chen et al., ).…”

Voluntary Chronic Heavy Alcohol Consumption in Male Rhesus Macaques Suppresses Cancellous Bone Formation and Increases Bone Marrow Adiposity

“…Heavy alcohol consumption increases bone marrow adiposity in growing rodents (Alund et al., ; Howe et al., ; Maddalozzo et al., ; Maurel et al., 2012b), a response observed in the present study in young adult male rhesus macaques. Osteoblasts and bone marrow adipocytes originate from the same bone marrow mesenchymal stem cells, and in vitro studies suggest that, at high concentrations, alcohol decreases osteoblast number by modulating the differentiation program of stem cells to form adipocytes at the expense of osteoblasts (Chen et al., ; Wezeman and Gong, ).…”

Effects of Acupoint Application Therapy with TianGui Powder on Osteoporosis in Ovariectomized Rats through TGF‐β1 and Smad2/3 Signaling Pathway

“…Tissue morphology not only verifies the results of bone mass detection but also shows the conditions of osteoblasts, osteoclasts, bone cells, and marrow cavities in a more intuitive way 22,23 . The results of this study showed that the microstructure and morphology of bone trabecula in model rats were damaged to different degrees, which is consistent with previous reports 24,25 . The results showed that microstructure and bone tissue morphology were significantly improved through AAT with TGP, confirming the effectiveness of AAT with TGP and provided experimental evidence for its clinical application in PMOP.…”