LASIK术中负压吸引对兔视网膜组织氧自由基的影响

Vacuum suction on oxygen radicals of rabbit retina in LASIK

目的观察LASIK术中负压吸引对新西兰兔视网膜组织氧自由基的影响。方法用LASIK负压吸引装置持续吸引新西兰兔右眼30s、60s、300s或间断吸引30s2次,左眼为对照,于1h、1d、7d后测定视网膜组织中超氧化物歧化酶(superoxide dis-mutase,SOD)、过氧化氢酶(catalase,CAT)、谷胱甘肽过氧化物酶(glutathion peroxidase,GRH-px)活性及丙二醛(malondialdehyde,MDA)含量,并观察视网膜组织在电镜下的形态学改变。结果酶学及MDA检测:负压吸引30s组SOD、CAT和GRH-px各酶活性稍有降低,MDA生成量也有所增加,但第7天时接近正常水平[第7天时4项指标在视网膜组织蛋白中含量分别为(162.49±17.39)nU.mg-1、(2.25±0.73)nmol.mg-1、(5.37±1.00)U.mg-1、(2.40±0.67)U.mg-1)]。负压吸引60s组与之相比,酶活性降低以及MDA生成增加更为明显,持续时间也较长[第7天时4项指标在视网膜组织蛋白中含量分别为(149.64±13.51)nU.mg-1、(2.64±0.71)nmol.mg-1、(3.31±0.51)U.mg-1、(1.82±0.91)U.mg-1]。间断负压吸引30s2次组的结果则介于前二者之间[第7天时4项指标在视网膜组织蛋白中含量分别为(157.16±11.95)nU.mg-1、(3.84±1.13)nmol.mg-1、(3.69±1.61)U.mg-1、(3.08±0.50)U.mg-1]。而负压吸引300s组与以上3组相比,酶活性降低及MDA生成增加最为显著,持续时间最长,且第7天时实验组与相应对照组之间差异比第1天更为显著[第7天时4项指标在视网膜组织蛋白中含量分别为(140.01±14.32)nU.mg-1、(2.40±0.89)nmol.mg-1、(3.65±0.79)U.mg-1、(2.01±0.48)U.mg-1]。组织形态学变化:各实验组视网膜组织结构改变均比较轻,只可见视细胞内节线粒体轻度肿胀变性,内核层细胞核周间隙增宽,内质网轻度扩张等改变。结论负压吸引的确引起视网膜组织内氧自由基增加并诱发视网膜组织结构的轻微变化。

Objective To investigate the effects of vacuum suction on the oxygen radicals in retina of New Zealand rabbits in laser in situ kerato-mileusis （LASIK）. Methods Suction device was used in LASIK to increase the intraocular pressure of right eye for 30,60,300 seconds or 30 seconds twice with interruption separately. Left eyes were control groups. At 1 hour, 1 day and 7 days, activities of superoxide dismutase （SOD）, eatalase （CAT）, glutathion peroxidase （GRH-px） and the level of malondi-aldehyde （MDA） were measured;The morphological changes of retinal tissue was compared with the control groups. Resuits With enzymology and MDA measurement, activities of superoxide dismutase,eatalase,glutathione peroxidage were depressed with the level of MDA rising and recovered on the 7th day in the 30 seconds group,and the concentrations of protein were（ 162.49 ± 17.39）nU · mg^-1 , （2.25 ±0.73 ）nmol · mg^-1 , （5.37 ± 1.00） U · mg^-1 , （ 2.40 ± 0.67 ） U· mg^-1 ,respectively, at the 7th day;Antioxidant enzymes were depressed and the level of MDA rose, and the continuance of these changes was longer in 60 seconds group ,and the concentrations of protein four these four index were （ 149.64 ± 13.51 ）nU · mg^-1 , （2.64 ±0.71 ）nmol · mg^-1 , （3.31 ±0.51 ）U · mg^-1 , （ 1.82 ± 0.91 ） U · mg^-1 ,respectively, at the 7th day;The changes of the 30 seconds twice-suction group were between the two groups above, and the concentrations of protein for these four index were （ 157.16 ± 11.95 ） nU· mg^-1,（3.84±l.13）nmol· mg^-1,（3.69±1.61）U· mg^-1,（3.08 ±0.50）U· mg^-1,respectively,at the 7th day. The changes of 300 seconds group were most obvious and lasted longest. On the 7th day the difference between experimental group and control group became more obvious than that on the first day, and the concentrations of protein for these four index were （ 140.01 ± 14.32 ） nU · mg^-1 ,（2.40 ±0.89） nmol · mg^-1, （3.65±0.79）U · mg^-1 , （2.01±0.48）U · mg^-1, respectively,at the 7th day. The morphological changes of all groups were some slight. It could be observed that mitochondrias swelled slightly in rod and cone inner segment. The interspaces around nuclear widened a little and endoplasmic reticulum dilated slightly in inner nuclear layer. Conclusion The vacuum suction can bring the increase of the oxygen radicals and a little changes in retinal tissue.