Varilek G W, Neil G A, Bishop W P, Lin J, Pantazis N J
Department of Internal Medicine, University of Kentucky College of Medicine, Lexington 40536-0084, USA.
Am J Physiol. 1995 Sep;269(3 Pt 1):G445-52. doi: 10.1152/ajpgi.1995.269.3.G445.
Nerve growth factor (NGF) exists in the gut of adult rats. The cells responsible for NGF synthesis in the gut remain unknown. IEC-6 and Caco-2 cells, established cell culture models of intestinal epithelial cells, were studied to determine whether intestinal epithelial cells, were studied to determine whether they synthesize and release NGF. Conditioned media from both IEC-6 and Caco-2 cells stimulated neurite outgrowth in both rat pheochromocytoma (PC-12) cells and sensory neurons derived from embryonic chick dorsal root ganglia (DRG). The addition of anti-NGF antibody blocked neurite outgrowth in PC-12 cells and partially blocked outgrowth in DRG cells. An NGF-enzyme-linked immunosorbant assay readily detected immunoreactive NGF in conditioned media from both cell lines, whereas cellular extracts from IEC-6, Caco-2, and isolated rat intestinal epithelial cells had low levels of immunoreactivity. Caco-2 monolayers primarily secreted NGF from the basolateral compartment, and interleukin-1 enhanced its secretion. IEC-6, Caco-2, and isolated rat intestinal epithelial cells expressed NGF mRNA as determined by reverse transcription polymerase chain reaction. These observations suggest that intestinal epithelial cells are capable of NGF synthesis.
神经生长因子（NGF）存在于成年大鼠的肠道中。肠道中负责NGF合成的细胞仍不清楚。研究了IEC-6和Caco-2细胞（肠道上皮细胞的既定细胞培养模型），以确定肠道上皮细胞是否合成并释放NGF。来自IEC-6和Caco-2细胞的条件培养基在大鼠嗜铬细胞瘤（PC-12）细胞和源自胚胎鸡背根神经节（DRG）的感觉神经元中均刺激了神经突生长。添加抗NGF抗体可阻断PC-12细胞中的神经突生长，并部分阻断DRG细胞中的神经突生长。一种NGF酶联免疫吸附测定法很容易在两种细胞系的条件培养基中检测到免疫反应性NGF，而IEC-6、Caco-2和分离的大鼠肠道上皮细胞的细胞提取物的免疫反应性水平较低。Caco-2单层主要从基底外侧区室分泌NGF，白细胞介素-1可增强其分泌。通过逆转录聚合酶链反应确定，IEC-6、Caco-2和分离的大鼠肠道上皮细胞表达NGF mRNA。这些观察结果表明肠道上皮细胞能够合成NGF。
