曲安奈德对视网膜裂孔光凝愈合的影响

The effects of intravitreal triamcinolone acetonide on the healing of retinal perforation after photocoagulation

目的观察玻璃体腔注射曲安奈德(TA)对视网膜裂孔光凝愈合的影响。方法8只实验兔双眼制作视网膜裂孔模型,光凝孔周,左眼注入4mgTA作为实验组,右眼注入平衡液作为对照组,光镜和电镜观察双眼裂孔光凝斑,Western blot法测定双眼视网膜裂孔处组织内转化生长因子β2(TGF-β2)的表达。结果光镜下两组损伤均主要累及色素上皮层、视锥视杆层、外核层。电镜下仅在对照组发现感光细胞与色素上皮细胞之间微绒毛交叉及色素上皮细胞与邻近细胞之间桥粒连接。实验组裂孔光凝后局部视网膜组织内TGF-β2的表达量为0.308±0.057,对照组为0.418±0.036,两组比较差异有统计学意义(P<0.01)。结论玻璃体腔注射TA有阻碍视网膜裂孔光凝后愈合的风险。

Objective The triamcinolone acetonide （TA） is applied to inhibit the development of proliferative vitreoretinopathy （PVR）.This study was designed to observe whether the intravitreal administration of TA influent the healing of retinal perforation after photocoagulation in an animal model mimicking the clinical photocoagulation of retinal perforation.Methods0.5mL C3F8 was injected intravitreally into both eyes of 8 pigmented rabbits to create a ＂gas vitrectomy＂.One week later,laser pipe was inserted into the intraocular through pars plana to touch the retina to create 2 retinal holes in each eye under the surgical microscope.Retinal photocoagulation was performed around the tear by frequency doubled laser,and 4 mg TA was injected intravitreally in the left eye of each rabbit as experimental group and balance fluid to the right eye as control group.The animals were killed and eyeballs were enucleated 2 weeks after injection for the histological examination under the light microscope and transmission electron microscope.TGF-beta2 level in retina around the retinal hole was detected by means of Western blot.ResultsThe increase of pigment particles in retinal pigment epithelium（RPE） and the migration of RPE cells were seen,and retinal photoreceptors were obviously decreased around the photocoagulation spot under the light microscope in both experimental group and control group.Under the transmission electron microscope,the proliferation of pigment granule,vacuolar degeneration of endocytoplasmic reticulum and mitochondria in the RPE cells were displayed in control group,and the proliferation of pigment granule and vacuolar degeneration of mitochondria in RPE cells and intact basal membrane of RPE cells were found in experimental group.Western blot assay revealed that TGF-beta2 expression in retina in experimental group was （0.308±0.057）,and that in control group was（0.418±0.036）,presenting a significant difference between these two groups （t=5.67,P〈0.01）.ConclusionIntravitreal injection of TA may have potential unfavorable effect on the healing of retinal hole after photocoagulation.This procedure may inhibit secretion of TGF-beta2 and delay the local repair of cellular suborgans structure,such as desmosome and microvilli-cross.