Effect of melatonin on some bone turnover markers in ovarectomized rats

ABSTRACT

This study was carried out to evaluate the effect and the mechanism of action of melatonin on some bone markers in ovarectomized bone loss in rats. 32 female albino rats underwent either bilateral laparotomy [sham, n=8] or bilateral ovarectomy [Ovx, n=24]. The Ovx rats were divided into 3 groups, each of 8 rats; Vehicle-treated [Ovx], estrogen-treated [E2] and melatonin-treated [Mlt] group. After 14 weeks treatment, blood and urine were collected. Serum osteoprotegerin [OPG], inhibin, follistatin, and alkaline phosphatase [ALPase] were determined as bone markers. In addition, urinary Deoxypyridinoline [uDPD] was assayed. Serum OPG, inhibin and follistatin levels significantly decreased upon Ovx. They increased upon either treatment with E2 or Mlt with non- significant difference in between as compared to Ovx group. In addition, serum ALPase and uDPD significantly increased on Ovx and decreased with either therapy as compared to Ovx one with non- significant difference between both therapies. The results revealed that administration of Mlt inhibited high bone turnover and prevented calcium loss in ovarectomized rats. This may be through increasing OPG, inhibin and/or follistatin levels. Mlt could be a candidate for the treatment of postmenopausal osteoporosis