基质细胞衍生因子-1在Wistar大鼠视网膜上的生理性表达

Expression of stromal cell-derived factor-1 in retina of rat

目的研究正常成体大鼠视网膜基质细胞衍生因子(SDF-1)的生理性表达情况。方法取正常Wistar成年大鼠视网膜进行抗SDF-1和抗PCK免疫组织化学染色,镜下观察结合半定量图像分析;实时定量RT-PCR测定视网膜神经上皮层SDF-1mRNA含量,与内参基因βactin比较。结果正常大鼠视网膜神经上皮可见SDF-1表达,其阳性结果多位于视网膜内层,视神经无明显染色。PCK在视网膜神经上皮上无明显表达。实时定量RT-PCR证实在健康成体大鼠视网膜神经上皮存在一定量的SDF-1mRNA。结论正常成年大鼠视网膜神经上皮层存在SDF-1的生理性表达,其生理作用及调控机制有待进一步研究。

Objective Stromal cell-derived factor-1 （SDF-1） is a newly found chemokine,which plays an important role in inducing postnatal vasculogenesis. Although it is accumulated in the vitreous body during some pathologic states,seldom research has focused on its expression at retina of adult animal. The purpose of this study was to investigate whether and how SDF-1 is physically expressed at retina of adult eye. Methods After fixed by 4% paraformaldehyde and embedded in paraffin,retinas of 26 healthy adult Wistar rats were studied by immunochemistry and digital photomicrograph analysis to detect the locations and levels of the expression of SDF-1 and pan cytokeratin （PCK）. The ratio of integrated optical density （IOD） to area of interest （AOI） was calculated to assess the intensity of positive staining. Values of z and P were determined by Wilcoxon-Mann-Whitney test. The SDF- 1mRNA level in retina of rat was quantified by the means of real-time RT-PCR. Results The positive immunohistochemical staining for SDF-1 was found mainly locating at the inner part of retina,especially at inner nuclear layer and ganglion cell layer rather than optic nerves. No positive staining in retina of rat for PCK was found. Inter-quartile range of IOD/AOI was 4 ×10^-4 to 1.1 ×10^-3 for SDF-1 and 4×10^-5 to 9×10^-5for PCK （z = 6. 335 ,P 〈0.01 ）. The SDF-1mRNA in retina of rat detected by real-time RT-PCR. Copies of SDF-1 mRNA were 3.58×10^-4 and 2.23×10^-4 respectively in 2 samples. In term of the ratios of copies of SDF- 1 mRNA to those of 13actin,one was 0.013 and the other one was 0.021. Conclusion SDF-1 is expressed constitutively at retina of adult rat. Further studies should focus on its physical function and regulation.