Green D G, Kapousta-Bruneau N V, Hitchcock P F, Keller S A
Department of Ophthalmology, University of Michigan, Ann Arbon 48104-1687, USA.
Invest Ophthalmol Vis Sci. 1997 Apr;38(5):919-29.
The Krd mouse has a deletion in chromosome 19 that includes the Pax2 gene locus. The aim of this study was to characterize in detail how these retinas differ from normal.
Both electroretinographic and anatomic methods were used to assess visual function. Full-field flash electroretinograms (ERGs) and planimetric densities were obtained from Krd and control animals.
Measurements of the ERG show that in the Krd mice, both a- and b-wave amplitudes are attenuated relative to control by amounts that vary from animal to animal. The b-wave of the ERG generally is affected more severely than the a-wave. However, there is little or no shift of the curves relating the b-wave and a-wave amplitude to the intensity of the stimulus. Also, no change in the response kinetics seems to be associated with the attenuated responses. Estimates of planimetric cell density in the outer nuclear, inner nuclear, and ganglion cell layers show significant cell losses in affected animals that are more pronounced proportionally in the inner layers. Comparisons between electrophysiological and histologic measurements made on each eye show good correlation between the reduction in the ERG components and the magnitude of cell losses.
These experiments show that the eyes of Krd mice have reduced ERGs and reduced cellular density. There is a loss of cells in all layers of the retina, but the inner layers are affected more severely. Consistent with this, the b-wave is reduced more than the a-wave. The normal functional dependency of the ERG on stimulus intensity and the normal response kinetics suggest the cellular losses are not associated with changes in cellular function.
Krd小鼠在19号染色体上存在缺失，该缺失包含Pax2基因座。本研究的目的是详细描述这些视网膜与正常视网膜的差异。
采用视网膜电图和解剖学方法评估视觉功能。从Krd小鼠和对照动物获取全视野闪光视网膜电图（ERG）和平面密度。
ERG测量结果显示，在Krd小鼠中，a波和b波的振幅相对于对照均有衰减，衰减程度因动物而异。ERG的b波通常比a波受到的影响更严重。然而，将b波和a波振幅与刺激强度相关联的曲线几乎没有或没有偏移。此外，似乎没有任何反应动力学的变化与衰减反应相关。对外核层、内核层和神经节细胞层的平面细胞密度估计显示，受影响动物存在明显的细胞损失，在内层中比例更为明显。对每只眼睛进行的电生理测量和组织学测量之间的比较表明，ERG成分的降低与细胞损失的程度之间存在良好的相关性。
这些实验表明，Krd小鼠的眼睛ERG降低，细胞密度降低。视网膜各层均有细胞丢失，但内层受到的影响更严重。与此一致的是，b波的降低比a波更多。ERG对刺激强度的正常功能依赖性和正常反应动力学表明，细胞损失与细胞功能的变化无关。
