No abstract

The effect of alcohol on rabbit bone marrow and on the differentiation of mouse bone marrow stromal cells was investigated. Alcohol was administered intragastrically at a dose of 10 mL/kg/day for 1 to 6 months. Alcohol induced a significant increase in serum lipid peroxides, triglyceride, and cholesterol, and a reduction in superoxide dismutase activity. Fatty infiltration in the liver and adipogenesis in bone marrow were found histologically after alcohol administration. Fat cell hypertrophy and proliferation and diminished hematopoiesis in the subchondral area of the femoral head were observed. Triglycerides were deposited in osteocytes, which became pyknotic, and the percentage of empty osteocyte lacunae increased. None of these abnormal changes were detectable in the control group. In the in vitro study, the marrow stromal cells were treated with increasing (0.03, 0.09, and 0.15 mol/L) concentrations of ethanol for 4 to 21 days. Alcohol induced the differentiation of the cells into adipocytes. The number of adipocytes increased with longer durations of exposure to ethanol and with higher concentrations. Cells treated with ethanol also showed diminished alkaline phosphatase activity and expression of osteocalcin. These novel findings indicate that alcohol can directly induce adipogenesis, decrease osteogenesis in bone marrow stroma, and produce intracellular lipid deposits resulting in the death of osteocytes, which may be associated with the development of osteonecrosis, especially in patients with long-term and excessive use of alcohol.

No abstract

Green tea has been reported to possess antioxidant, antitumorigenic, and antibacterial qualities that regulate the endocrine system. Previous epidemiological studies found that the bone mineral density (BMD) of postmenopausal women with a habit of tea drinking was higher than that of women without habitual tea consumption. However, the effects of green tea catechins on osteogenic function have rarely been investigated. In this study, we tested (-)-epigallocatechin-3-gallate (EGCG), one of the green tea catechins, on cell proliferation, the mRNA expressions of relevant osteogenic markers, alkaline phosphatase (ALP) activity and mineralization. In a murine bone marrow mesenchymal stem cell line, D1, the mRNA expressions of core binding factors a1 (Cbfa1/Runx2), osterix, osteocalcin, ALP increased after 48 h of EGCG treatment. ALP activity was also significantly augmented upon EGCG treatment for 4 days, 7 days and 14 days. Furthermore, mineralizations assayed by Alizarin Red S and von Kossa stain were enhanced after EGCG treatment for 2-4 weeks in D1 cell cultures. However, a 24-h treatment of EGCG inhibited thymidine incorporation of D1 cells. These results demonstrated that long-term treatment of EGCG increases the expressions of osteogenic genes, elevates ALP activity and eventually stimulates mineralization, in spite of its inhibitory effect on proliferation. This finding suggests that the stimulatory effects of EGCG on osteogenesis of mesenchymal stem cells may be one of the mechanisms that allow tea drinkers to possess higher BMD.