Effects of chronic sleep deprivation on bone mass and bone metabolism in rats.

Xiaowen Xu,Tiantian Wang,Xuemei Fu,Dan Li,Liang Wang,Liying Chen,Fan Yang,Yan Zhang,Yuanyuan Xie,Wujie Zhai,Weifeng Ma,Tianjiao Su,Yuanzheng Ma,Qiong Chen

doi:10.1186/s13018-016-0418-6

Abstract

BackgroundThis study aimed to assess the effects of chronic sleep deprivation (CSD) on bone mass and bone metabolism in rats.MethodsTwenty-four rats were randomly divided into CSD and control (CON) groups. Rats were subjected to CSD by using the modified multiple platform method (MMPM) to establish an animal model of CSD. Biochemical parameters such as levels of serum N-terminal propeptide of type I procollagen (PINP), N-terminal cross-linking telopeptide of type I collagen (NTX), growth hormone (GH), estradiol (E2), serum 25(OH)D, and calcium (Ca) were evaluated at 0, 1, 2, and 3 months. After 3 months, each fourth lumbar vertebra and the distal femoral metaphysis of the left extremity of rats were harvested for micro-computed tomography scans and histological analysis, respectively, after the rats were sacrificed under an overdose of pentobarbital sodium.ResultsCompared with rats from the CON group, rats from the CSD group showed significant decreases in bone mineral density (BMD), bone volume over total volume, trabecular bone thickness, and trabecular bone number and significant increases in bone surface area over bone volume and trabecular bone separations (P < 0.05). Bone histomorphology studies showed that rats in the CSD group had decreased osteogenesis, impaired mineralization of newly formed bones, and deteriorative trabecular bone in the secondary spongiosa zone. In addition, they showed significantly decreased levels of serum PINP (1 month later) and NTX (3 months later) (P < 0.05). The serum 25(OH)D level of rats from the CSD group was lower than that of rats from the CON group after 1 month (P < 0.05).ConclusionsCSD markedly affects bone health by decreasing BMD and 25(OH)D, deteriorating the bone microarchitecture, and decreasing bone formation and bone resorption markers.

Highlights

This study aimed to assess the effects of chronic sleep deprivation (CSD) on bone mass and bone metabolism in rats
Body weight The body weight of rats from both groups increased over time, but the increase in body weight of rats from the CSD group was significantly less than that of rats from the CON group after 1 week of sleep deprivation (Fig. 1, P < 0.001)
Bone mass and bone microstructure analysis The representative micro-CT images revealed that rats from the CSD group had fewer trabecular bone structures than those from the CON group (Fig. 2)

Summary

Introduction

This study aimed to assess the effects of chronic sleep deprivation (CSD) on bone mass and bone metabolism in rats. An increasing number of people are having insufficient sleep, and approximately one third of adults report getting less than 6.5 h of sleep on each weeknight [1]. It has been reported that compared to individuals who sleep for 8 h, those who sleep for 6 h or less have significantly lower total and regional BMD [15] Another clinical survey showed that patients with sleep disorders, women and elderly people, have an increased risk of osteoporosis [16]. Several studies have suggested that CSD is associated with lower BMD; one study showed that sleeping for both less than and more than 8–9 h/day increases the risks of having osteoporosis [19]. Some studies showed that the association between sleep duration and BMD was not significant [20, 21]

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