Authors: Hayato Kinoshita Naohisa Miyakoshi Yuji Kasukawa Sadaoki Sakai Ayako Shiraishi Toyohito Segawa Kentaro Ohuchi Masashi Fujii Chie Sato Yoichi Shimada
Publish Date: 2015/05/06
Volume: 34, Issue: 2, Pages: 171-178
Abstract
Glucocorticoids cause secondary osteoporosis and myopathy characterized by type II muscle fiber atrophy We examined whether a new vitamin D3 analogue eldecalcitol could inhibit glucocorticoidinduced osteopenia or myopathy in rats and also determined the effects of prednisolone PSL and/or eldecalcitol on musclerelated gene expression Sixmonthold female Wistar rats were randomized into four groups PSL group 10 mg/kg PSL E group 005 µg/kg eldecalcitol PSL + E group and control group PSL eldecalcitol and vehicles were administered daily for 2 or 4 weeks Right calf muscle strength muscle fatigue crosssectional areas CSAs of left tibialis anterior muscle fibers and bone mineral density BMD were measured following administration Pax7 MyoD and myogenin mRNA levels in gastrocnemius muscles were also determined Muscle strength was significantly higher in the PSL + E group than in the PSL group p 005 after 4 weeks but not after 2 weeks No significant difference in muscle fatigue was seen between groups at 2 or 4 weeks CSAs of type II muscle fibers were significantly larger in the E group and the PSL + E group than in the PSL group at 4 weeks p = 00093 p = 00443 respectively Eldecalcitol treatment for 4 weeks maintained the same BMD as the PSL + E group After 2 weeks but not 4 weeks eldecalcitol treatment significantly increased Pax7 and myogenin mRNA expression in gastrocnemius muscle and PSL also stimulated myogenin expression Eldecalcitol appears to increase muscle volume and to protect against femur BMD loss in PSLadministered rats and it may also stimulate myoblast differentiation into early myotubes
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