Objective To study the effect of lead on the calcium absorption and bone development in weanling rats. Methods Totally 80 weanling Wistar rats were equally divided into normal control (given with pure water and standard feed, including 1.15% calcium), lead group (given 1.0 g/L lead acetate water and standard feed), lead+low calcium group (1.0 g/L lead acetate water and feed including 0.69% calcium), and lead+high calcium group (1.0 g/L lead acetate water and feed including 1.72 % calcium). The development of rats was observed. Serum contents of osteocalcin and parathormone,and bone levels of lead and calcium in the femur were determined. The femur was examined with histological method. Another 5 Wistar rats received gastric irrigation of 10% lead acetate for 5 d, 5 more rats served as control, and then their absorption of calcium was detected with 45CaCl2. Results Lead and low calcium inhibited the development of rat remarkably, with the content of osteocalcin, the length and diameter of the femur decreased. High calcium antagonized these effects of lead. The absorption of calcium in rats was repressed by lead. Conclusion Bone depression by lead may be due to that lead inhibits the absorption of calcium in rats, and the supplement of calcium is helpful to minimize the repression.

Objective: To study the effect of calcium on osteocalcin(OC) and parathyroid hormone (PTH) in rat exposed to lead. Method: Wistar rats were randomly divided into control group, lead group, low-calcium+lead group and high-calcium+lead group. The content of calcium and lead in bone, OC and PTH of rat with different treatments were detected. At the same time, RT-PCR analysis was used to determine the expression of OC and PTHr1. Results: Lead decreased the content of calcium in bone and OC. The expression of OC was inhibited, and the level of PTH and the expression of PTHr1 increased, which could be enhanced by low calcium treatment, but high calcium treatment could antagonize these effects of lead. Conclusion: Supplementation of calcium in diet could extenuate the toxicity of lead on bone in rat.

Objective:To observe the inhibitory effects of VD3 and Tamoxifen on ER-negative breast cancer cells transfected with human recombinant pVDRE-Tk-ER? eukaryotic expression plasmid in vivo. Method:A recombinant human ER? expression plasmid containing 4 copies of VDRE and Tk promoter was introduced into the ER-negative MDA-MB-231 breast cancer cell. The transformed breast cancer cells were inoculated into athymic nude mice. 4 w after tumor inoculation,mice bearing the tumor of approximately 200 mm3 were treated with 0.5?g/kg of VD3 and/or 50mg/kg of Tamoxifen(SC) for 20d. The tumor volume was precisely measured,concurrently HE stain and Ki-67 immunohistochemical(IHC) assay were performed to detect the anti-proliferative effect of Vit D3 in combination with Tamoxifen in vivo. Results:After 20d of treatment,VD3 and Tamoxifen synergistically decreased the tumor volume as compared with control group. And the IHC results also showed that the Ki-67 expression was significantly inhibited by co-treatment of VD3 and Tamoxifen,which means the arrest of cell cycle progression. Conclusion:VD3 could effectively restore the sensitivity of ER-negative breast cancer cells to Tamoxifenby inducing the expression of exogenous ER? gene through the VDRE and Tk promoter in vivo.

Objective To observe the synergistic effects of Herceptin(HER)and 9-cis-retinoic acid (9-cis-RA) on HER2/neu positive breast cancer cells in vivo. Method MCF-7 breast cancer cells transfected with exogenous HER2 gene were inoculated into athymic nude mice. Four weeks after tumor inoculation,mice bearing a tumor of 200 mm3 in volume approximately were selected to be treated with HER and/or 9-cis-RA(SC) for 20d. After that tumor volume was precisely measured,concurrently the HE staining and Ki-67 immunohistochemical (IHC) assay were performed to detect the anti-proliferative effect of HER in combination with 9-cis-RA in vivo. Results After 3 w of treatment,HER and 9-cis-RA synergistically decreased the tumor volume as compared with control group. IHC results showed that Ki-67 expression was significantly inhibited by co-treatment of HER and 9-cis-RA,which means the arrest of cell cycle progression. Conclusion Herceptin and 9-cis-RA could synergistically inhibit the proliferation of HER2 positive breast cancer cells in vivo.

Objective To examine the effects of different n-6/n-3 polyunsaturated fatty acid(PUFA) ratio in gap junctional intercellular communication (GJIC) in breast cancer cell lines. Methods After MCF-7(ER + )and MDA-MB-231(ER - )cells were treated respectively with n-6/n-3 polyunsaturated fatty acid ratio (1-10), Ki-67 expression in nuclear by immunocytochemistry, connexin 26 and 43 expression in cytoplasm and membrane by Western blotting, and GJIC by scrape-loading dye transfer method were performed. Results Immunocytochemistry showed that pure n-6 and 10∶1 n-6/n-3 increased Ki-67 expression (P

Objective To establish the animal model bearing BRCA1-overexpressing breast tumor in athymic mouse so as to investigate the effects of lovastatin (LOV) on the growth of the xenograft tumor and understand its mechanism. Methods After amplification and identification, pcDNA3-beta-HA-hsBRCA1 plasmid was transfected into MCF-7 cells by liposome transfection to deliver a high level of BRCA1 gene expression examined with RT-PCR and Western blotting (named MCF-7 BRCA1 ). Twenty athymic mouse models of BRCA1-overexpressing xenograft tumor were established by respectively inoculating 2?10 6 MCF-7 cells and MCF-7 BRCA1 cells to right anterior part of the back. Four weeks later, lovastatin at the dose of 50 mg/kg was injected around the tumor for 10 d. Then the tumor volume was measured, the histopathological changes of xenograft tumor were observed with electron microscope by HE staining, the expressions of cyclinD1, CDK4 mRNA and protein were detected by RT-PCR and Western blotting. Results The athymic mouse model of xenograft breast tumor was successfully established after MCF-7 cells were transfected with pcDNA3-beta-HA-hsBRCA1 plasmids. The incidence rate of xenografted breast tumor in athymic mouse was 100%. Routine HE staining of paraffin-embedded section proved that the tumor was a mammary carcinoma in nature. Treated with lovastatin for 10 d, the tumor volume of mouse implanted with MCF-7 cells was large (0.48 cm 3 ) and there was a slight change in expressions of cyclinD1, CDK4 mRNA and protein, while the tumor volume of mouse inoculating MCF-7 BRCA1 cells was small (0.21 cm 3 ) and the expressions of cyclinD1, CDK4 mRNA and protein obviously descended. The two groups showed diminution in cancer cells and increase of necrosis, more significant in those mice inoculating MCF-7 BRCA1 cells. Conclusion Lovastatin could resist the proliferation of BRCA1-overexpressing breast tumor, which may relate to the decrease of the cyclinD1, CDK4 mRNA and protein expressions.

Objective To study the effects of different n-6/n-3 polyunsaturated fatty acid ratio on the lipid metabolic gene expression and MAPK activity in breast cancer cell lines. Methods MCF-7 and MDA-MB-231 cells were treated with n-6 polyunsaturated fatty acid, or n-3 polyunsaturated fatty acid, or the mixture of n-6/n-3 polyunsaturated fatty acid at ratio of 1∶1, 5∶1, 10∶1. The cell proliferation capacity was detected by MTT, the expression of lipid metabolic gene (COX-2, 5-LOX, PPAR? and PPAR?) were assayed by RT-PCR, MAPK phosphorylation levels were detected by Western blotting. Results COX-2 mRNA expression was not found in MCF-7 cells. As compared to normal control group, pure n-6 and 10∶1 n-6/n-3 promoted cell proliferation, up-regulated the expression of COX-2, 5-LOX, PPAR? and PPAR? mRNA , increased MAPK phosphorylation levels in MCF-7 and MDA-MB-231 cells (P

Objective: To explore the effect of acute hypoxia on the appetite and expression of neuropeptide Y (NPY) in rat hypothalamus. Methods: Wistar rats were randomly divided into control group, 3 000 m group, 4 000 m group , 5 000 m group and 6 000 m group for different times (1d, 2d and 3d respectively) . The change of appetite was observed and the expression of NPY in hypothalamus of rats was measured by immunohistochemical method. Results: (1) After acute hypoxia, the appetite of rats decreased. (2) The expression of NPY of the test groups and the normal group was decreased in arcuatus, paraventricular and dorsal median nucleus of the hypothalamus after acute hypoxia. Conclusion: Acute hypoxia might inhibit feed intake of rats, and decreased expression of NPY in hypothalamus, which may be one of the important reasons for loss of appetite.

Objective To study the effect of 1,25-dihydroxyvitamin D_(3) and Tamoxifen on cell cycle distribution and apoptosis of MDAMB-231 cells transfected with ER? expression vector containing vitamin D response element.Methods The 4 VDRE-Tk sequence of VDRE-pGL3 reporter vector was cloned into ER?/pcDNA3.1+ vector and then was transfected into MDA-MB-231 breast cancer cells.MDA-MB-231~(VDRE-ER?) breast cancer cells were treated with 1,25-dihydroxyvitamin D_(3) and Tamoxifen to observe their pro-apoptotic effect by TUNEL and to determine whether cell cycle progression could be repressed by FCM.Results As compared with control group,MDA-MB-231~(VDRE-ER?) cells at G_(0)/G_(1) phase increased profoundly after treated with 1,25-dihydroxyvitamin D_(3) and Tamoxifen for 72 h.Meanwhile,1,25-dihydroxyvitamin D_(3) and Tamoxifen synergistically induced the apoptosis of MDA-MB-231~(VDRE-ER?) cells.Conclusion Transfection of VDRE-Tk-ER? expression vector into ER?-negative breast cancer cells could effectively recover its responsiveness to Tamoxifen under the induction of 1,25-dihydroxyvitamin D_(3) by blocking the cell cycle progression and inducing apoptosis.

The influence of individual vitamin on immunity has been described before. In this report, the comprehensive effect of vitamin A, E, riboflavin, pyridoxine and folic acid on the immune response was studied in the BALB/C mice. Animals were divided into five groups:control group, one-third requirement group, double requirement group, triple requirement group and restored group (feeding insufficient diet for six weeks, and then normal diet for another two weeks). The results showed that the percentages of the peripheral blood T cell, Tu cell were diminished significantly in the deficient group in comparison to controls, on the contrast, those in double and triple requirement groups increased obviously, and also did the restored group supplemented normally but no difference in the percentage of Ty in all groups. The study also showed a positive correlation between the relative, absolute thymic weight and the percentage of the peripheral blood T cell. The changes stated above of the peripheral blood T cell and its sub-populations are partially owing to the abnormality of the thymic tissue, but the distribution of lymphocyte shouldn't be neglected. The study found the plaque forming cells (PFC) of spleen, aud the ratio of 3H-thymidine incorporating into splenic lymphocyte after exposure to ConA, PHA and LPS in vitro were increased significantly in double and triple requirement groups; but with the vitamin complex under supply, the former was requced significantly, the latter was comparable to the controls. The PFC increased markedly and no difference with the double group after insufficient animals fed normal diet for two weeks. It is therefore not surprising that the vitamin complex plays a special role in the differentiation and maturation of PFC. According to the study, the vitamin complex may influence the growth of lymphoid tissue, the differentiation and maturation of immunocompetent cells and functional manifestation by mainly affecting the contents of cAMP, cGMP of lymphocyte, and the metabolism of nucleic acid and protein.