激光光凝法诱导大鼠高眼压模型的有效性评估

目的　评估激光光凝法诱导大鼠高眼压模型的有效性。方法　５３２ｎｍ激光光凝小梁网法诱导大鼠左眼高眼压（ｎ＝４５，右眼为对照眼），评估激光后大鼠眼压、视网膜神经节细胞及视网膜电图的变化；采用Ｔｏｎｏ-Ｌａｂ眼压计测量清醒状态下的双眼眼压，每天１次；激光后３周，采用双盲法计数双眼视网膜铺片上免疫组织化学法标记的阳性节细胞数；记录大鼠双眼基线及处死前的视网膜电图。结果　激光后９０．７０％（３９／４３眼）的大鼠眼压升高，其中需要第２次激光者占７４．４２％（３２／４３眼）。激光后右眼的眼压为（１６．１３±１．１１）ｍｍＨｇ（ｎ＝３９；１ｋＰａ＝７．５ｍｍＨｇ）；左眼中有２８．２１％眼（ｎ＝１１）眼压升高（１８．２７±２．５３）ｄ，其余眼（ｎ＝２８）眼压升高（７．９３±２．４０）ｄ，两者的眼压分别为（３５．５９±４．５７）ｍｍＨｇ、（２１．５６±３．０６）ｍｍＨｇ，两者的峰值眼压分别为（６３．３６±４．２３）ｍｍＨｇ、（４９．４３±７．２２）ｍｍＨｇ；实验眼与对照眼之间的峰值眼压差为（３１．１３±８．６４）ｍｍＨｇ，累积眼压差为（１８２．３１±１４０．３５）ｍｍＨｇ，左右眼的眼压相比差异有显著统计学意义（Ｐ＝０．０００）。激光后３周，两个高眼压组的节细胞数相比，差异无统计学意义（Ｐ＝０．６９３），左眼的节细胞丢失率为６７．４％ ±１４．８％，与右眼相比差异有显著统计学意义（Ｐ＝０．０００）。左眼视网膜电图明适应ｂ波、ＰｈＮＲ波及暗适应ｂ波的潜伏期与激光前相比，差异均有统计学意义（Ｐ＝０．０００、０．０４６、０．０００），其振幅与激光前相比，差异也均有显著统计学意义（Ｐ＝０．００１、０．０００、０．０００），而明适应ａ波的潜伏期、振幅及暗适应ａ波的潜伏期与激光前相比，差异均无统计学意义（Ｐ＝０．１３８、０．１９８、０．０９２）。结论　激光光凝法诱导大鼠眼压升高成功率较高，但持续时间有限，峰值眼压过高，且需重复激光，高眼压引起的节细胞丢失率高，视网膜电图提示视网膜损伤主要累及双极细胞及节细胞。

Efficiency evaluation on laser-induced hypertensive rat model

Objective To evaluate the efficiency of laser-induced hypertensive rat model. Methods Experimental glaucoma was induced in left eyes of 45 Fischer rats by a diode laser with wavelength of 532 nm aimed at trabecular meshwork. Efficiency of glaucomatous model was evaluated by assessing the success rate and duration of high intraocular pressure and IOP induced retinal histological and functional changes. IOP was measured by a Tonolab tonometer in conscious rats every day. At 3 weeks after laser,the degree of retinal ganglion cells ( RGC ) loss was assessed by a masked, semiautomated counting of Tuj-I labeled RGC. electroretinography ( ERG) was recorded from both eyes using custom made electrodes at baseline and just prior to euthanasia. Results After laser photocoagulation.the success rate of high IOP was 90. 7% (39/43 ) .the rate for second laser was 74. 42% ( 32/43 ) . IOP in right eyes ( n = 39) ,28. 21% of left eyes( n = 11 ) and 71. 7g% of left eyes ( n = 28) were ( 16. 13 + 1. 11 ) mmHg ( I kPa = 7. 5 mmHg) , ( 35. 59 +4. 57 ) mmHg and ( 21. 56 + 3. 06 ) mmHg , respectively , peak IOP in these eyes were ( 22. 36 +2. 88) mmHg, ( 63. 36 + 4. 23 ) mmHg and (49. 43 + 7. 22 ) mmHg,respectively, peak IOP difference and cumulative IOP difference between experimental and control eyes were (31. 13 + 8. 64 ) mmHg and ( 182. 31 + 140. 35 ) mmHg, respectively,the difference between left and right eyes was statistically significant (P = 0. 000). High IOP in left eyes persisted for ( 18. 27 + 2. 53) days ( n = 11) and (7. 93 + 2. 40) days(n = 28 ) , respectively. At 3 weeks after laser photocoagulation, RGC loss in two left-eye groups was not statistically significant ( P = 0. 693 ) , however ,in comparison with right eyes , RGC loss in left eyes was ( 67. 4 + 14. 8 ) % (P = 0. 000) . There were significantly prolonged latencies for photopic b-wave, PhNR wave and scotopic b-wave (P =0. 000 ,P = 0. 046 .P = 0. 000) . and the amplitude of these waves were also significantly decreased ( P = 0. 001 ,P = 0. 000 ,P = 0. 000 ) . However , the parameters of photopic ( latency, amplitudes) and scotopic ( latency) a-wave were not statistically significant ( P = 0. 138 ,P = 0. 198 ,P = 0. 092 ) . Conclusion The success rate of laser induced high IOP is high in this experiment .but the duration of high IOP is short. the peak IOP is too high , and the rate for second laser is high. RGC loss induced by increased IOP is significantly higher than previously reported , and ERG changes indicate retinal damage is mainly involved in the bipolar cells and RGC.