组织病理学切片与频域OCT对大鼠视网膜组织形态的对比研究

Evaluation of rat retina by histopathological examination and spectral domain high-resolution optical coherence tomography

目的研究组织病理学切片(石蜡切片和冰冻切片)及频域OCT在评价大鼠视网膜各亚层结构中的特点及其异同,并分析其原因。设计实验研究。研究对象健康Brown Norway(BN)大鼠12只。方法选择正常BN大鼠12只(24眼),频域OCT(Cirrus HD-OCT)对大鼠视网膜距视盘2 PD处进行扫描并测量各亚层厚度;处死大鼠后左眼行视网膜石蜡切片,右眼行冰冻切片,并分别测量距视盘2 PD处视网膜各亚层厚度,分析其形态学特点,并对所得实验数据进行统计学分析。主要指标大鼠视网膜各个亚层的厚度及形态学特点。结果石蜡切片所测大鼠距视盘2 PD处视网膜厚度(166.98±9.07)μm,冰冻切片所测大鼠距视盘2 PD处视网膜厚度(209.06±10.41)μm,频域OCT测量值为(208.75±11.19)μm。频域OCT图像与冰冻切片测量结果接近,两者之间差异无统计学意义(P=0.425);而石蜡切片与其他两者之间差异均有统计学意义(P均<0.001)。除内核层外,频域OCT、石蜡切片以及冰冻切片测量的大鼠视网膜各亚层厚度间差异均有统计学意义(P均<0.05),石蜡切片较冰冻切片和频域OCT所测量的视网膜各亚层均有不同程度的收缩,但组织层次更加完整清晰,可以更清楚地显示至细胞水平。通过频域OCT可以得到大鼠视网膜图像,但内界膜、神经纤维层和神经节细胞层之间分界不明显;冰冻切片方便快捷,相对石蜡切片更接近OCT活体测量的结果,但容易造成玻璃体后脱离致视网膜神经纤维层不完整。结论组织病理学切片(石蜡切片和冰冻切片)及频域OCT在评价大鼠视网膜各亚层结构中具有各自独特的特点,又具有一定的一致性。在进行视网膜的定量研究时,冰冻切片和频域OCT更加准确,而在定性研究特别是细胞水平的研究中,石蜡切片的组织形态更加完整清晰。

Objective To investigate the characteristics, similarities and differences of the histopathological examination （paraffin and frozen sections） and the spectral domain high-resolution optical coherence tomography （HD-OCT） used for evaluation of rat retinal sublayers. Design Experimental study. Participants Twelve healthy Brown Norway （BN） rats. Methods The Cirrus HD-OCT was used to evaluate the thickness of the retinal sublayers of all the eyes in a peripapillary distribution at a distance about 2 disc diameters. The left eyes from the rats were made into paraffin sections and the right eyes were made into frozen sections after rats were sacrificed. The thickness of rat retinal sublayer approximately 2 optic disc diameters away from the optic disc were measured. The data were statistical- ly analyzed. Main Outcome Measures The thickness and morphological characteristics of rat retinal sublayer. Results The thickness of BN rat retina was （166.98 ± 9.07）μm that measured in paraffin sections, （209.06 ± 10.41 ）μm in frozen sections, and （208.75 ± 11.19）μm in the OCT images, respectively. The thickness of the retina measured in the frozen sections was similar to that measured in the OCT images, and there was no significant difference statistically （P=0.425）. The significant difference was found between paraffin sec- tions and the other two groups （P 〈0.001）. Except the thickness of inner nuclear layer, the thickness of other sublayers was significantly different among the three groups（P 〈0.05）. The thickness of the rat retinal sublayer in paraffin sections was perceptibly less, but the or- ganizational structure was more complete and clearer, and it showed more clearly at the cellular level. The rat retina images can be ob- tained by the spectral domain HD-OCT, but the boundaries between sublayers were not clear in some sublayers. The examination of fi＇ozen section was convenient anti quickly, and the results were consistent with that measured in the OCT images. But it was likely to induce the incompletion of retinal nerve fiber layer caused by posterior detachment of vitreous. Conclusion Each method has its own u- nique characteristics on evaluation of rat retinal sublaycr, but also some consistency. When conducting retinal quantitative study, frozen sections and OCT images are more accurate. When making qualitative research, the paraffin sections of tissue morphology is clearer and more eomplete, especially when fi）cusing on cellular level.