Palm Tocotrienol Preserves Trabecular Osteocyte Indices and Modulates the Expression of Osteocyte Markers in Ovariectomized Rats.

Abstract

Background/Objective: Palm tocotrienol has bone-protective properties in animal models, yet its underlying mechanism remains unclear. Given osteocytes' role in bone homeostasis, this research aimed to investigate the effects of palm tocotrienol on the quantity of osteocytes and the expression of osteocyte-specific markers in ovariectomized rats. Methods: Adult female rats (Sprague Dawley; three-month-old; n = 6/group) were randomly divided into baseline, sham control, ovariectomized control, unemulsified palm tocotrienol (UPT), emulsified palm tocotrienol (EPT), and positive control. The baseline group was euthanized without intervention, whereas the sham group underwent a laparotomy procedure in which the ovaries were not excised. The other groups underwent bilateral removal of the ovaries and subsequently received UPT (100 mg/kg/day, 50% vitamin E), EPT (100 mg/kg/day, 25% vitamin E), or a combination of glucosamine sulfate (250 mg/kg/day) and calcium carbonate (1% in drinking water). Control groups were induced with similar gavage stress with olive oil. After 10 weeks, all rats were sacrificed for bone and serum analysis. Results: UPT and EPT significantly increased trabecular osteocyte and total lacunae numbers (p < 0.05 versus ovariectomized control). Both treatments significantly reduced mRNA expression levels of dentin matrix protein-1 (p < 0.05 versus ovariectomized control), whereas sclerostin mRNA expression was unchanged (p > 0.05 versus ovariectomized control). However, neither UPT nor EPT improved circulating or skeletal redox status (p > 0.05 versus ovariectomized control). Conclusions: Palm tocotrienol may support bone health by preserving the quantity of trabecular osteocytes and modulating osteocyte-mediated bone remodeling. Further research is required to elucidate its precise mechanisms.