• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.309-317
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• 2000

Bisphosphonates inhibit bone resorption in vivo and in vitro. Currently proposed mechanism of action of bisphosphonates involves both direct effect on osteoclasts and indirect effect through the mediation of osteoblasts. Recent understanding of molecular mechanism of osteoclastogenesis indicates that osteoclast differentiation is quite tightly regulated by signaling molecules from differentiating osteoblasts. Therefore this investigation was designed to elucidate the effect of bisphosphonate on osteoblast differentation. For this purpose, in vitro effects of etidronate and alendronate on the expression of Cbfa1 a master control gene of osteoblast differentiation, several bone marker genes, and formation of calcified nodules were evaluated. To evaluate the effect of bisphosphonate on calcified nodule formation, osteoblasts isolated from rat calvaria were cultured in a-MEM containing $10^{-4},\;10^{-5},\;10^{-6}M$ of etidronate or $10^{-6},\;10^{-7},\;10^{-8}M$ of alendronate for 15 days, and then stained by alizarin red to determine mineralization. To evaluate the effect of bisphosphonate on osteoblast differentiation, osteoblast cells were cultured in a-MEM containing $10^{-4},\;10^{-5},\;10^{-6}M$ of etidronate or $10^{-6}$ M of alendronate for 8 days. And then total RNA was extracted and northern blot analysis was done to examine the expression of Cbfa1, type I collagen, alkaline phosphatase, osteopontin and osteocalcin. The results were as follows: 1. Etidronate suppressed the calcification of bone nodule in dose dependent manner, while alendronate didn't. 2. The expression of Cbfa1 was decreased dose dependently by etidronate, but increased by alendronate. 3. Etidronate suppressed the expression of type I collagen, osteopontin and osteocalcin in dose dependent manner however alendronate promote the expression of osteoblast marker gene. 4. The expression of alkaline phosphatase was not affected either etidronate nor alendronate. These results suggest that etidronate suppressed the expression of Cbfa1 in dose dependent manner, and consequently the expression of osteoblast marker genes, such as type I collagen, osteopontin and osteocalcin were also suppressed in similar manner. And finally this decreased expression of osteoblastic marker gene prevent calcined bone nodule formation.

• Journal of Yeungnam Medical Science
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• v.12 no.1
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• pp.32-47
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• 1995

Glutathione(GSH) has a very important role in detoxification of cells and is closely related to antitumor drug-resistance of cancer cells. In order to evaluate the importance of glutathione metabolism in the drug-resistant cancer cells, the concentration of celluar GSH and activities of ${\gamma}$-glutamylcysteine synthetase(GCS), ${\gamma}$-glutamyl transpeptidase (GGT) and glutathione S-transferases(GST) in the adriamycin, vincristine, or cisplatin resistant L1210 (L1210AdR, L1210VcR, or L1210Cis) sublines were measured. Expression and amplification of GCS, GGT, and GST-${\pi}$ genes were also observed in the parent Ll210 and the drug-resistant Ll210 sublines. The concentration of GSH was increased 5.34 fold in L1210Cis, 2.83 fold in L1210VcR, and 1.78 fold in L1210AdR, compared to L1210. The activities of GCS and GGT were increased in drug-resistant L1210 sublines. The GST activity was increased in L1210VcR and L1210Cis but decreased in L1210AdR compared to Ll210. Expression of GCS, GGT, and GST-${\pi}$ genes were increased in the resistant L1210 sublines compare to the parent L1210 in northern blot analyses. Overexpression of GCS, GGT, and GST-${\pi}$ were observed in the resistant sublines, and the increases of the concentration of glutathione and the activities of GCS and GGT in the resistant sublines may be involved in a part of the drug-resistance in the resistant sublines.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.1
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• pp.29-40
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• 2010

This study was aimed at investigating the gene expression profile in basal ganglia of cadmium exposed rat based on cDNA array analysis. For cDNA array analysis, adult Sprague-Dawley male rats (350 ${\pm}$ 25 g) were intraperitoneally injected with 2.0 mg/kg body weight/day of CdCl2 (0.3 ml) for 5 days. For doserelated gene expression analysis rats were intraperitoneally injected with 0.0, 0.1, 0.3, 1.0 mg/kg body weight/day of CdCl$_2$ for 5 days. Control rats were injected with equal volume of saline. Cadmium concentration of brain was analyzed by atomic absorption spectrophotometer. For cDNA array, RNA samples were extracted from basal ganglia and reverse-transcribed in the presence of [${\alpha}$32P]-dATP. Membrane sets of the Atlas Rat 1.2 array II and Toxicology array 1.2 (Clontech, Palo Alto, CA) were hybridized with cDNA probe sets. RT-PCR was employed to validate the relative gene expression patterns obtained from the cDNA array. Northern blot hybridization methods were employed to assess the dose-related gene expression. Among the 2352 cDNAs, 671 genes were detected in both array sets and 63 genes of 38 classes showed significant (more than two fold) changes in expression. Thirty five of these genes were up-regulated and twenty eight were down-regulated in the cadmium exposed group. According to the dose-related gene expression analysis, heat shock 27 kDa protein (HSP27), neurodegeneration-associated protein 1 (Neurodap 1) genes were significantly up-regulated and melatonin receptor 1a (Mel1a), Kinesin family member 3C (KIF3C), novel kinesinrelated protein (KIF1D) genes were significantly downregulated even in the low-dose of cadmium exposed group (0.1 mg/kg body weight/day). Conclusions Sixty three genes detected in this study can give some more useful informations about the cadmium-induced neurotoxicity in the basal ganglia. As well as, HSP27, Neurodap1, Mel1a, KIF3C and KIF1D genes may be useful for the study of the cadmium-induced neurotoxicity because these genes showed dramatic changes of mRNA levels in response to the low dose of cadmium exposure.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.194-200
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• 2014

Monodehydroascorbate reductase (MDHAR) is an important enzyme that plays a role in the detoxification of reactive oxygen species (ROS) by maintaining reduced pool of ascorbate through recycling the oxidized form of ascorbate. In this study, we isolated a PagMDHAR1 gene from Populus alba ${\times}$ P. glandulosa, and investigated its expression characteristics. The PagMDHAR1 cDNA encodes a putative 434 amino acids containing FAD- and NAD(P)H-binding domains. Southern blot analysis indicated that a single nuclear gene encodes this enzyme. Northern hybridization analysis revealed that PagMDHAR1 is highly expressed in both suspension cells and flower tissues, while its expression levels were enhanced by drought, salt, cold, wounding and ABA. Therefore, PagMDHAR1 might be expressed in response to abiotic stress through the ABA-mediated signaling pathway in this poplar species, suggesting that the PagMDHAR1 plays an important role in the defense mechanisms against oxidative stress.

• Journal of Preventive Medicine and Public Health
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• v.38 no.3
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• pp.330-336
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• 2005

Objectives : The aim of this study was to investigate the effects of bisphenol A (BPA), an estrogen-like environmental endocrine disrupter, on the placental function and reproduction in rats. The mRNA levels of the placental prolactin-growth hormone(PRL-GH) gene family, placental trophoblast cell frequency and reproductive data were analyzed. Methods : The pregnancies of F344 Fisher rats ($160g{\pm}20g$) were detected by the presence of the copulatory plug or sperm in the vaginal smear, which marked Day 0 of pregnancy. Pregnant rats were divided into three groups. The control group was intraperitoneally injected with a sesame oil vehicle. The two remaining groups were injected with 50 or 500 mg/kg B.W/day of BPA, resuspended in sesame oil, on either days 7 to 11 or 16 to 20 of pregnancy, with the rats sacrificed on either day 11 or 20, respectively. The mRNA levels of PRL-GH and Pit-1a and b isotype genes were analyzed by Northern blot hybridization and reverse transcription-polymerase chain reaction. The hormone concentrations were analyzed by radioimmunoassay, and the frequency of the placental trophoblast cells observed by a histochemical study. Reproductive data, such as the placental weight and litter size, were surveyed on day 20. The fetal weight was surveyed for 4 weeks after birth. A statistical analysis was carried out using the SAS program (version 8.1). Results : The mRNA levels of the PRL-GH gene family, such as placental lactogen I, Iv and II, prolactin like protein A, C and Cv, and decidual prolactin-related protein were significantly reduced due to BPA exposure. The mRNA levels of the Pit-1a and b isotype genes, which induce the expression of the PRL-GH gene family in the rat placenta, were also reduced due to BPA exposure. The PL-Iv and PL-II concentrations were reduced in the BPA exposed group. During the middle to last stage of pregnancy (Days 11-20), a high dose of BPA exposure reduced the frequency of spongiotrophoblast cells, which are responsible for the secretion of the PRL-GH hormones. Reproductive data, such as the placental and fetal weights and the litter size, were reduced, but that of the pregnancy period was extended in the BPA exposed compared to the control group. Conclusions : BPA disrupts the placental functions in rats, which leads to reproductive disorders.

• Journal of Preventive Medicine and Public Health
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• v.37 no.2
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• pp.157-165
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• 2004

Objectives : This study aimed to investigate the toxic effects of chromium (VI) on the placental function and reproduction in rats. For the study, the placental prolactin-growth hormone (PRL-GH) gene expression, placental trophoblast cell differentiation and reproductive data were analyzed. Methods : The pregnancies of F344 Fisher rats were checked by the presence of a copulatory plug or sperm in the vaginal smear, which was defined as day 0 of the pregnancy. Pregnant rats were divided into the three groups. The control group was given tap water (chromium level < 0.001 ppm) and the remaining groups were given 250 or 750 ppm of chromium (VI) [as potassium dichromate], from day 7 to 19 of the pregnancy. Rats were sacrificed at days 11 and 20 of pregnancy. The mRNA levels of PRL-GH and Pit-1a and b isotype genes were analyzed by Northern blot hybridization and reverse transcription-polymerase chain reaction (RT-PCR). The hormonal concentration was analyzed by radioimmunoassay, and the differentiation of placental trophoblast cells were observed by histochemical studies. Reproductive data, such as placental and fetal weights, pregnancy period, and litter size, were surveyed at day 20 of pregnancy and after birth. A statistical analysis was carried out using the SAS program (version 8.1). Results : The mRNA levels of the prolactin-growth hormone (PRL-GH) family of genes were dose dependently reduced by chromium exposure. The mRNA levels of Pit-1a and b isotype genes that induce the expression of the PRL-GH family of genes were also reduced by chromium exposure. The PRL-GH hormonal concentration in the rat placenta, fetus and maternal blood were decreased by chromium exposure. In the middle stage of pregnancy (day 11), a high dose of chromium suppressed the differentiation of spongiotrophoblast cells that secret the PRLGH hormones. In the last stage of pregnancy (day 20), a high dose of chromium induced apoptosis of placental cells. Reproductive data, such as placental and fetal weights, litter size, were reduced, but the pregnancy period was extended in the group exposed to chromium compared with the controls. Conclusion : Chromium (VI) disrupts the ordered functions of the placenta, which leads to reproductive disorders in rats.