miRNAs作为放射性视神经病变分子标志物的筛选及其靶基因的鉴定和功能分析

Radiation-induced optic neuropathy（RION）is a common ocular complication induced by the treatment beam for tumors.RION is also an severe radiation damage which can cause blindness after human exposure to radiation.The key point to reduce the severe damage of RION is how to realtime detection and early diagnosis for RION after radiation exposure. However, there are still without effective methods for RION early detection and diagnosis, which causes the result of RION associated visual loss. For the past few years,screening special small non-coding RNAs (miRNAs) as biomarkers for diseases has attracted many scientists' attention.Using miRNAs micoarray analysis in our previous study,we have screened the changes of 12 miRNAs expression in cultured ganglion cells following radation exposure in vitro. Based on the previous results,we will establish the stable RION research animal model. Expression of special miRNAs related to RION in circulating blood,aqueous humor and vitreous will be detected at different periods of RION. The aim of the project is to find some special miRNAs which can act as RION molecular biomarkers,and also analyze the biological functions of these miRNAs and their tagart genes on RION occurrence and development.Through this study,we will provide the experimental basis of miRNAs biomarkers for RION realtime detection and early diagnosis,and miRNAs biomarkers analysis also can be used as a rapid and effective method to detect optic nerve injury after radiation occupational exposure and radiation events.

放射性视神经病变（RION）是肿瘤放射治疗后的常见并发症, 也是放射线暴露突发事件中，可导致失明的严重放射性损伤。如何能在放射暴露后对RION进行实时监测并早期诊断，是降低RION危害性的关键，也是目前制约RION有效治疗的难题。近年来，筛选非编码微小RNA（miRNAs）作为特定疾病发生发展的分子标志物已成为研究热点。本课题前期应用miRNAs微阵列芯片，在体外成功筛选出了视神经放射损伤后差异表达的12个miRNAs，在此基础上将进一步建立动物模型，检测RION不同发展阶段外周血、眼房水和玻璃体中特异性miRNAs的表达规律，尝试找到可以作为RION分子标志物的miRNAs，并分析和鉴定其靶基因，探讨miRNAs及其靶基因在RION产生中的生物学作用。研究结果将不仅解决放疗后RION实时监测和早期诊断问题，而且在职业放射暴露和放射突发事件时，可作为一项快速有效的视神经损伤检测生物指标。

放射性视神经病变是头颈部肿瘤放射治疗后的严重并发症，表现为无痛性不可逆性急剧视力下降，不仅降低了患者的生存质量，而且容易引发不必要的医患纠纷，近年来越来越受到相关研究领域的重视。本研究通过体外建立放射损伤细胞模型，观察了放射损伤对视网膜神经节细胞形态及活性的影响，应用 miRNAs 微阵列芯片技术共筛选出了12个放射损伤后具有统计意义的差异表达 miRNAs，实时荧光定量PCR对这12 miRNAs 做了进一步鉴定和确认，并初步分析了这些 miRNAs 的靶基因及其功能；应用基因转染及RNA沉默技术，研究了 Escin对视网膜色素上皮细胞氧化损伤的保护作用及其分子机制，研究结果表明，Escin 的抑制作用是通过激活AKT-Nrf2信号通路，进而活化并使Nrf2 磷酸化来实现的；应用线粒体膜电位检测技术，研究了新型小分子肽MTP-131对视网膜神经节细胞损伤的保护作用及其机制，研究结果表明，MTP-131能显著减少细胞内LDH释放，抑制线粒体去极化，通过降低活性氧的产生及减少细胞色素 C 释放，保护视网膜神经节细胞的慢性损伤；观察并分析了复方樟柳碱治疗缺血性视神经病变的临床疗效，明确了复方樟柳碱对慢性视神经损伤的效果并探讨了其作用机制。综上这些研究结果，对进一步阐明放射性视神经病变的发病机制，探讨放射性视神经病变发生发展的分子标记物，以及放射性视神经损伤新的有效的治疗方法，具有积极的临床意义。