摘要
目的 探讨胰岛素样生长因子Ⅱ (IGF Ⅱ )调节成骨细胞一氧化氮 (NO)水平及诱导型(iNOS)和内皮型一氧化氮合酶 (eNOS)mRNA转录的作用。方法 不同浓度和不同时间IGF Ⅱ作用于小鼠成骨样细胞株MC3T3 E1细胞后 ,采用噻唑蓝 (MTT)比色法检测细胞增殖、硝酸还原酶法测定细胞培养物上清NO浓度、逆转录聚合酶链式反应检测细胞的iNOS和eNOSmRNA转录水平。结果 1μg/LIGF Ⅱ作用 72h ,10和 10 0 μg/LIGF Ⅱ分别作用 2 4、4 8和 72hMC3T3 E1细胞 ,其MTT值均明显升高 (P <0 0 5、P <0 0 1)。 10 0 μg/LIGF Ⅱ分别作用 4 8和 72h ,细胞iNOSmRNA水平及其上清液中NO水平均显著下降 (P <0 0 1) ,但IGF Ⅱ以不同浓度及时间作用的细胞eNOSmRNA水平均无明显改变 (P >0 0 5 )。结论 1～ 10 0 μg/LIGF Ⅱ均能促进MC3T3 E1细胞增殖 ,此作用可能与IGF Ⅱ维持细胞低水平NO有关。较高浓度的IGF Ⅱ (10 0 μg/L)可在转录水平上下调MC3T3 E1细胞iNOS基因表达 ,但不影响eNOSmRNA的转录 ,这可能是MC3T3 E1细胞维持低水平NO的机制之一。
Objective To study the effects of insulin-like growth factor Ⅱ (IGF-Ⅱ) on regulating the levels of nitric oxide (NO) and the 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 intervals of time,MTT colorimetry was used for examining the cell proliferation. Nitrate reductase method was applied for detecting the NO concentrations in cell culture supernatants and RT-PCR employed for determining the levels of cellular iNOS and eNOS mRNAs.Results After the MC3T3-E1 cells were treated with IGF-Ⅱ at the dosages of 1 μg/L for 72 h,10 and 100 μg/L for 24,48 and 72 h respectively,all the MTT values increased markedly ( P <0.05 or P <0.01). After the cells were treated for 48 and 72 h at the dosage of 100 μg/L IGF-Ⅱ respectively,the levels of NO in the supernatants of cell cultures and cellular iNOS mRNA decreased significantly ( P <0.01). However,the levels of eNOS mRNA in the cells treated with any of the IGF-Ⅱ dosages for the different times were stable ( P >0.05).Conclusions IGF-Ⅱ at the dosages of 1～100 μg/L showed the effects on promoting proliferation,which as probably due to the maintenance of low NO levels. Inducible NOS gene expression at the level of transcription was down regulated in the MC3T3-E1 cell treated with higher dosage of IGF-Ⅱ (100 μg/L) but eNOS mRNA was not,which might be one of the mechanisms for the maintenance of low NO levels.
出处
《中华口腔医学杂志》
CAS
CSCD
北大核心
2004年第3期201-204,共4页
Chinese Journal of Stomatology
基金
浙江省科技厅基金资助项目 (99110 3 115 )
