Niblock M M, Brunso-Bechtold J K, Lynch C D, Ingram R L, McShane T, Sonntag W E
Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Brain Res. 1998 Aug 31;804(1):79-86. doi: 10.1016/s0006-8993(98)00645-3.
Previous studies have reported changes in insulin-like growth factor I (IGF-I) mRNA expression during early postnatal development of the rat brain. Although changes in IGF-I gene expression have been documented in a wide range of central nervous system structures during early development and investigated in the hippocampus during aging, no study has compared changes in IGF-I gene expression in different brain regions across the life span. The present study assessed the distribution of IGF-I gene expression using in situ hybridization in rats aged 2-30 months. Dot blots were used as a quantitative assessment of cortical IGF-I mRNA. Results indicate that both the distribution and levels of brain IGF-I mRNA do not change significantly between 2 and 30 months of age in the rat. However, in spite of relatively constant levels of mRNA, other studies from our laboratory have demonstrated that cortical IGF-I protein levels decrease 36.6% between 11 and 32 months of age, suggesting that IGF-I function is decreased with increasing age.
以往的研究报道了大鼠脑产后早期发育过程中胰岛素样生长因子I（IGF-I）mRNA表达的变化。虽然在早期发育过程中，IGF-I基因表达的变化已在广泛的中枢神经系统结构中得到记录，并且在衰老过程中对海马体进行了研究，但尚无研究比较整个生命周期中不同脑区IGF-I基因表达的变化。本研究使用原位杂交技术评估了2至30月龄大鼠IGF-I基因表达的分布情况。斑点印迹法用于对皮质IGF-I mRNA进行定量评估。结果表明，在2至30月龄的大鼠中，脑IGF-I mRNA的分布和水平均无显著变化。然而，尽管mRNA水平相对恒定，但我们实验室的其他研究表明，皮质IGF-I蛋白水平在11至32月龄之间下降了36.6%，这表明IGF-I功能随着年龄的增长而降低。
