经瞳孔温热疗法对急性高眼压大鼠视网膜神经节细胞的保护作用

The protective effect of transpupillary thermotherapy on retinal ganglion cells in rat with acute retinal ischemia-reperfusion

目的研究低阈值经瞳孔温热疗法(TTT)对急性高眼压大鼠视网膜神经节细胞(RGC)是否具有保护作用。设计实验研究。研究对象BN大鼠。方法采用810nm二极管激光机对10只大鼠视网膜进行热刺激,照射光斑1．2mm,能量50mW,照射时间20s,干预后3d光镜下观察视网膜形态结构的改变,免疫组化方法检测HSP70、HSP27在视网膜组织表达。采用上述激光参数,照射视网膜后3d,制作急性高眼压模型(TTT+I/R组,n=10),采用TUNEL法检测RGC层细胞凋亡数量,及计数高倍镜下RGC层细胞数,与未干预的急性高眼压模型组(I/R组,n=10)、单纯TTT干预组(TTT组)及正常对照组(n=6)进行比较。主要指标免疫组化染色RGC细胞数及RGC层细胞凋亡数。结果采用低阈值TTT可诱导BN大鼠视网膜神经节细胞HSP70及HSP27表达,且光镜下未出现明显视网膜脉络膜形态的改变。TTT+I/R组RGC层细胞凋亡数量明显少于I/R组(P=0．048),且前者RGC层细胞数量明显多于后者(P=0．016);TTT组与正常对照组比较RGC层细胞凋亡数量无显著性差异(P=0．882),但RGC层细胞数明显少于正常对照组(P=0．001)。结论低阈值TTT可诱导BN大鼠视网膜HSP70、HSP27表达,并在急性高眼压损伤下对大鼠RGC凋亡具有抑制作用。(眼科,2007,16:48-51)

Objective To study the protective effect of subthreshold transpupillary thermotherapy （TTT） on retinal ganglion cells （RGC） in rat with acute retinal ischemia-reperfusion. Design Experimental research. Participants Brown Norway （ BN ） rats. Methotis TTT was performed on 10 BN rats with 810-nm diode laser. The laser was aimed at retina with 1.2 mm spot size, and an exposure power of 50 mW and exposure duration of 20 seconds. 3 days after the laser irradiation, morphologic analysis was observed with light microscope, and heat shock protein （HSP） 70, 27 immunohistochemical staining were performed. With the same laser parameter, laser irradiation was performed 3 days before making rat retinal ischemia-reperfusion model （TTT＋I/R group, n=10）. The amount of cells and apoptosis cells （TDT-mediated biotin-dUTP nick-end labeling, TUNEL） of the RGC layer were counted and compared among retinal ischemia -reperfusion group（I/R group, n=10）, laser irradiation group （TTT group, n=10） and normal control group （n=6）. Main outcome measure The amount of apoptosis cell and total cell of RGC layer in immunohistochemical staining. Results HSP70 and HSP27 were induced on BN rat RGC layer using subthreshold TIT without tissue damage under a light microscope. TTT＋I/R group was compared with I/R group. The amount of apoptosis cell significantly reduced（P= 0.048）, and the amount of cell on RGC layer was larger in TTT＋ I/R group than in I/R group （P= 0.016）.Compared apoptosis cell in TIT group with normal group, there was no significant difference （P= 0.882）, but the amount of cell on RGC layer in TIT group was obviously declined（P= 0.001 ）. Conclusion HSP70 and HSP27 can successfully be induced on rat retina with subthreshold TTT, and apoptosis of RGC under acute high intraocular pressure was suppressed after the treatment of subthreshold TTT. （Ophthalmol CHN, 2007, 16： 48-51）