猫外层视网膜和脉络膜的年龄相关变化

取老年猫(12龄,2.5~3 kg)和青年猫(1~3龄,2~2.5 kg)各4只的视网膜,经4%多聚甲醛处理后用H.E染色以显示视网膜和脉络膜的结构。光学显微镜下观察感光细胞层、玻璃膜(Bruch’s membrane)结构的变化,计数色素上皮层(retinal pigment epithelium,RPE)细胞数、脉络膜毛细血管数,测量玻璃膜、脉络膜厚度,脉络膜毛细血管之间的距离。结果显示,与青年猫比较,老年猫视网膜感光细胞层结构杂乱;色素上皮细胞数显著下降;玻璃膜厚度无显著变化,出现较多碎片;脉络膜厚度明显变薄,脉络膜毛细血管数显著减小,脉络膜毛细血管之间的距离显著增大。推测老年猫脉络膜的退化可能是导致玻璃膜、色素上皮层的退化,进而导致感光细胞的功能衰退的重要原因。

Age-related Changes in the Outer Retina and Choroid of Cat

The retinae of 4 old cats(12 years,2.5-3 kg) and 4 young adult cats(1-3 years,2-2.5 kg) were collected.After treatment with 4% polyformaldehyde,the retinae were stained with H.E to visulize the structures of outer retina and choroid.Under light microscope,the structural changes of photoreceptor cell layer and Bruch's membrane were observed.The number of cells in retinal pigment epithelium and the number of choriocapillaries were counted,and the thickness of Bruch's membrane and choroid,as well as the distance between choriocapillaries were measured.Results showed that in old cats the structure of photoreceptor layer was disordered;the number of retinal pigment epithelium cells was significantly declined;the thickness of Bruch's membrane did not significantly change while more debris was built up;the thickness of choroid,the number of choriocapillaries decreased significantly;the distance between choriocapillaries increased significantly.We speculate that the degeneration in choroid of old cats might induce the degeneration in Bruch's membrane and retinal pigment epithelium,which may impair the function of photoreceptor layer.