首页|Effects of IGF-II on promoting proliferation and regulating nitric oxide synthase gene expression in mouse osteoblast-like cell

Effects of IGF-II on promoting proliferation and regulating nitric oxide synthase gene expression in mouse osteoblast-like cell

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Objective: To investigate the effects of insulin-like growth factor Ⅱ (IGF-Ⅱ) on promoting cell proliferation, regulating levels of cellular nitric oxide (NO) and mRNA transcriptions of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) in mouse osteoblast-like cells. Methods: Mouse osteoblastic cell line MC3T3-E1 was selected as the effective cell of IGF-Ⅱ. After the cells were treated with IGF-Ⅱ at different concentrations for different time duration,3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay was used to examine cell proliferation,and nitrate reductase method was applied to detect NO concentrations in cell culture supernatants and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to determine transcription levels of cellular iNOS and eNOS mRNAs. Results: After the MC3T3-E 1 cells were treated with IGF-Ⅱ at concentration of 1 ng/ml for 72 h, 10 and 100 ng/ml for 24,48 and 72 h respectively, all the MTT values increased (P<0.05 or P<0.01) with obvious dosage-time dependent pattern. NO levels of the MC3T3-E1 cells treated with 100 ng/ml IGF-Ⅱ for 48 h, and with 1, 10 and 100 ng/ml IGF-Ⅱ for 72 h were remarkably lower than that of the normal control, respectively (P<0.05 or P<0.01). After the cells were treated with 100 ng/ml IGF-Ⅱ for 48 h cellular iNOS mRNA levels were significantly decreased (P<0.01). But the levels of eNOS mRNA in the cells treated with each of the used IGF-Ⅱ dosages for different time duration did not show any differences compared with the normal control (P>0.05).Conclusion: IGF-Ⅱ at different concentrations could promote proliferation of mouse MC3T3-E1 cell. This cell proliferation promotion was associated with the low NO levels maintained by IGF-Ⅱ. Higher concentration of IGF-Ⅱ could down-regulate iNOS gene expression at the level of transcription but not affect transcription of eNOS mRNA, which might be one of the mechanisms for IGF-Ⅱ maintenance of the low NO levels in MC3T3-E 1 cells.

Insulin-like growth factor Ⅱ, Osteoblast, Proliferation, Nitric oxide synthase, Nitric oxide, Regulation

SUN Wei-lian、CHEN Li-li、YAN Jie、YU Zhong-sheng

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Department of Stomatology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China

Department of Medical Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou 310006, China

Affiliated Children's Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China

浙江省科技厅资助项目

991103115 was

2005

浙江大学学报(英文版)(B辑:生物医学和生物技术)
浙江大学

浙江大学学报(英文版)(B辑:生物医学和生物技术)

影响因子:0.798
ISSN:1673-1581
年,卷(期):2005.6B(7)
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