Long-term supplementation with young coconut juice help prevent bone loss of orchidectomized rats by increasing connectivity density, percentage bone volume and osteoblast-/osteocyte-(ERα-/ ERβ-) immunoreactive cells of the L5 vertebra and femur

Abstract

Adult male rats were orchidectomized (ORX) and treated with 17β-estradiol or young coconut juice (YCJ) for ten weeks. Their femur and L5 vertebra were dissected, and the percentage of bone volume was measured using a Micro-CT scan. Immunohistochemistry was used to detect ERα and ERβ to determine if the osteoporotic protective effects of YCJ were due to the attachment of the YCJ active components(s) to estrogen receptors. It was found that both ERα and ERβ were found in osteocytes and osteoblasts, but not osteoclasts. Compared to normal rats, the percentage of bone volume and number of osteoblast- and osteocyte- reactive cells of both femur and L5 were significantly reduced in ORX rats. Those numbers in the ORX rats were restored to normal by injecting estradiol benzoate or by feeding YCJ to the rats, which was not dose-related. Significant correlations were detected between osteoblast-/osteocyte- (ERα-/ERβ)-reactive cells vs. serum E2 level. The optimal dose of this study was 10 mL/kg BW/ day for ERα-of both osteoblasts and osteocytes and 40 mL/kg BW/day for ERβ-of both osteoblasts and osteocytes. The results suggest that YCJ may be as efficient as estradiol benzoate in attenuating osteoporosis, probably by being a selective estrogen receptor moderator.