BACKGROUND:High fat diet (HFD) can induce overweight and obesity,which have been considered to positively affect bone mineral density (BMD) in adults.However,it is unclear how HFD affects the bone development during childhood.OBJECTIVE:To determine the effect of HFD on bone development in young female mice.METHODS:Twelve female CD1 mice were fed with either HFD or normal fat diet (NFD) starting at 4-week of age for 10 weeks.The bone mineral content (BMC),BMD,fat and lean mass were examined in 14-week old mice using dual-energy X-ray absorptiometry,and bone biomechanical properties were also evaluated using three-point bending test.Serum concentration of bone metabolic markers was measured using enzyme immunoassay.Femora were sectioned in the transverse plane and stained with hematoxylin and eosin for observing the adiposity of bone marrow and changes in trabecular bone area.RESULTS AND CONCLUSION:The body weight and fat mass in HFD-treated mice were increased compared with those in NFD-treated mice,respectively.There were no significant differences between HFD-treated and NFD-treated mice in whole body BMD,BMC,bone area and lean mass.However,the spine BMC and bone area in HFD mice were significantly lower than that in NFD mice,while femoral BMD,BMC and bone area in HFD mice were significantly greater than that in NFD mice.But,there was no statistically different in bone biomechanical values between the two groups.Bone metabolic markers were lower in HFD mice than NFD mice,indicating the less active of bone metabolism in HFD mice.It is suggested that HFD can produce deleterious effect on bone during the active growing phase of young mice.Vertebral bone is more sensitive to this negative effect than cortical bone due to the decreased vertebral mineralization.Weight-bearing bone does not response sufficiently to compensate for the excessive weight gaining.

Objective To investigate the effects of trivalent arsenicals on ce ll proliferation and induction of apoptosis in human epidermal keratinocytes. Me thods Human benign epidermal keratinocytes (cell line HaCaT), human epidermal ca rcinoma cells(cell line A431) were cultured. After treatment with arsenous acid, inhibition of cellular growth was determined by measuring MTT dye absorption of living cells.Apoptosis was assessed with respect to morphological changes by li ght and electron microscopy and to cell cycle distribution by flow cytometry. An nexin-ⅴbinding assay was used to detect the early stage of apoptosis. Results With concentrations ranging from 0.5 to 10 ?mol/L, arsenous acid significantly inhibited the proliferation of HaCaT cells in a dose-and time-dependent manner . By light and electron microscopy, morphological changes revealed characteristi cs of apoptosis. But A431 cells showed no obvious change. DNA flow cytometric an alysis indicated that arsenous acid induced an arrest in G2M phase and sub-G1 p hase in HaCaT compared with A431 cells. The green flurorescence indicated early stage of apoptosis in HaCaT cells by annexin-V binding assay. Conclusion Arseno us acid may inhibit the proliferation of HaCaT cells and induce apoptosis, but d oes not affect A431 cell line obviously, which suggests that HaCaT cells are mor e sensitive to arsenous acid compared with A431 cells.

Objective To investigate the effects of leflunomide(A77 1726) on the proliferation and apoptosis of human keratinocytes. Methods Proliferating cell nuclear antigen (PCNA) of HaCaT cells was analyzed with crystal violet staining and immunohistochemistry. The moiphological change was assessed with hematoxylin and eosin staining. The changes of cell cycle and apoptosis rate were measured by flow cytome-try. Result Epidermal proliferation was inhibited by leflunomide, at concentration 5 ?mol/L or more, which was begun after 24 hrs and manifested by PCNA positive cell decreasing. With the increasing of time or dosage, the anti- proliferation effect of leflunomide was significant. Meanwhile, the PCNA positive cell de-creased respectively. There was no PCNA positive cell while the drug concentration achieved 200 ?mol/L. Therefore, leflunomide significantly inhibited the proliferation of HaCaT cells in a dose-dependent and time-dependent manner. The morphological change and cell cycle change was found but no change of apoptosis rate was measured. Conclusion Leflunmide can inhibit the proliferation of HaCaT cell, without the effect on its apoptosis.