Induction of drug resistance in Tca8113 cell line by exposing to chemotherapy drug / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the drug resistance changes in Tca8113 cell lines by exposing to carboplatin.</p><p><b>METHODS</b>The concentration of carboplatin added to Tca8113 cells was increased gradually and continually, which was to induce the carhoplatin-resistance in Tca8113 cells. The sensibility to drugs of the cells was analyzed by MTT method. Immunocytochemistry and RT-PCR were utilized to examine the expression of multidrug resistance proteins and genes.</p><p><b>RESULTS</b>After exposing to carboplatin, the Tca8113/CBP cells had higher drug-resistance to CBP, MTX, PYM, VCR and higher expression of MRP, GST-pi than Tca8113 cells.</p><p><b>CONCLUSION</b>Multidrug resistance of Tca8113/CBP is associated with over expression of MRP, GST-pi and MDR. Tca8113/CBP can provide an ideal model for multidrug resistance research.</p>

Piperazinyl estrone prevents bone loss in ovariectomized rats / 药学学报

<p><b>AIM</b>To determine the effect of piperazinyl estrone, a new estrogen derivative, on bone turnover, bone mass and uteri in ovariectomized rats.</p><p><b>METHODS</b>Female Sprague-Dawley rats were ovariectomized (OVX) or sham operated (sham) at the age of 3 months and treated with estrone (E) at 0.75 mg.kg-1.d-1, or with piperazinyl estrone (P-E) at 1 or 10 mg.kg-1.d-1, orally, for 3 months. At the time of death, the uterine weight was measured. Bone histomorphometric analysis of proximal tibial metaphyses (PTM) was performed in undecalcified sections.</p><p><b>RESULTS</b>Bone histomorphometric data showed that the percent trabecular area (% Tb.Ar) of OVX rats with bone high turnover was significantly decreased. The uteri were atrophied. The percent trabecular area (% Tb.Ar) of estrone treated group was increased in decreasing bone turnover manner. But the size and weight of uteri in this group were increased vs OVX group. The bone loss induced by OVX was preserved by P-E treatment, but the mechanism of maintaining bone is different from that of E-treated rats. P-E treatment in low dose did not decrease any bone formation indices, such as percent labeling perimeter, bone formation rate per bone volume (BFR/BV), except bone mineral apposition rate (MAR) compared with E-treated group, and maintained them at OVX level. The uteri were found to be in atrophy compared with the match dose (0.75 mg) of E-treated OVX rats. But rats treated with high dose of P-E showed the same change like E-treated group.</p><p><b>CONCLUSION</b>The finding of this study shows that lower dosage of piperazinyl estrone has effect on preventing the bone losses in OVX rats, while the bone formation and the uterus are not affected, thus supporting the hypothesis that piperazinyl estrone has the potential to prevent postmenopausal bone loss in women with less side effects.</p>

Effect of aging on the ability of growth and differentiation of rat bone marrow stromal cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To measure the osteogenesis and adipogenesis potentiality of rat marrow stromal cells (MSCs) derived from 3, 6, 9, 12-month-old doner rats.</p><p><b>METHODS</b>Rat MSCs were induced to osteoblast or adipocyte by osteogenic inducer or adipogenic inducer. In different times, 3 and 12-month-old rat MSCs were observed by histochemistry staining; the mRNA level of type I collagen and lipoprotein lipase of 3, 6, 9, 12-month-old rat MSCs were measured by RT-PCR.</p><p><b>RESULTS</b>The expression of alkaline phosphatase (ALP) of the control group and induced group of 12-month old rat MSCs was less than that of 3-month old rat MSCs after 1-week osteogenic induction. 12 days later, calcification was observed in 3-month old group. Lipid droplets occurred in the cells of 12-month old group after 2-day adipogenic induction, while these droplets occurred after 3-day or 4-day induction in 3-month old group. The mRNA level of type I collagen decreased with the increase of age. The mRNA level of lipoprotein lipase of younger rats was lower than that of older rats. Both of the changes were more significantly with the increase of the induction time.</p><p><b>CONCLUSIONS</b>With the increase of age, the ability of osteogenesis of rat MSCs decreased, but the ability of adipogenesis increased.</p>