摘要
Objective To determine the effects of insulin-like growth factor-1 （IGF-1） on the expression of preprotachykinin （PPT） mRNA encoding substance P （SP） and calcitonin gene-related peptide （CGRP） mRNA in cultured dorsal root ganglion （DRG） neurons with excitotoxicity induced by glutamate （Glu）. Methods DRGs were dissected from embryonic day 15 Wistar rats. DRG neurons were dissociated and cultured for 48 h and then exposed to Glu （0.2 mmol/L） or Glu （0.2 mmol/L） plus IGF- 1 （5 nmol/L, 10 nmol/L and 20 nmol/L） for 12 h. The DRG neurons in control group were exposed to only growth media throughout the experiment. After that, the living DRG neurons were observed under inverted phase contrast microscope and microphotographs were taken. The expression levels of PPT and CGRP mRNAs were detected by reverse transcriptionpolymerase chain reaction （RT-PCR）. Results IGF-1 could inhibit Glu-induced shortening of neurite. Besides, IGF-1 could significantly increase the levels ofPPT mRNA and CGRP mRNA in primary cultured DRG neurons with Glu-induced excitotoxicity, in a dose-dependent manner. Conclusion IGF-1 may exert neuroprotective effects on DRG neurons against Glu-induced excitotoxicity, probably through regulating the expression levels of PPT and CGRP mRNAs.
目的利用背根神经节(dorsalrootganglion,DRG)神经元,观察胰岛素样生长因子-1(insulin-like growth factor-1,IGF-1)对谷氨酸(Glu)神经毒性引起的编码P物质(substanceP,SP)的前速激肽原(preprotachykinin,PPT)mRNA和降钙素基因相关肽(calcitonin gene-related peptide,CGRP)mRNA表达下降的调节作用。方法取15d胎龄大鼠的DRG神经元,分散培养48h后,在培养液中加入Glu(0.2mmol/L),或同时加入不同浓度的IGF-1(5nmol/L,10nmol/L,或20nmol/L)孵育12h,利用倒置相差显微镜对神经元活细胞进行观察,并用RT-PCR法检测神经元中PPT和CGRP的mRNA表达水平。对照组DRG神经元培养液中不含Glu和IGF-1。结果Glu能引起神经元突起的缩短,而IGF-1则显著减弱这一作用。此外,Glu的神经毒性使得DRG神经元内PPT和CGRP的mRNA水平显著降低,而IGF-1则能明显抑制这种降低,且呈一定的浓度依赖性。结论IGF-1可能通过调节PPT和CGRP的mRNA表达水平,对DRG神经元产生保护作用。
基金
supported by the Natural Sciences Foundation of Shandong Province, China(No. Z2006C06)
the Science and Technology Development Project of Jinan Municipality of Shandong Province,China (No. 200705083, 200807046)
