Hassel Brant, Samuelson Don A, Lewis Patricia A, Gelatt Kirk N
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0126, USA.
Vet Ophthalmol. 2007 Nov-Dec;10 Suppl 1:38-45. doi: 10.1111/j.1463-5224.2007.00519.x.
It has been recently demonstrated that trabecular meshwork (TM) cells within the canine iridocorneal angle (ICA) contain smooth muscle actin (smA) and possess contractile abilities that probably alter aqueous outflow. As the number of trabecular meshwork cells in glaucomatous canine eyes have been found to be less than those in age-matched nonglaucomatous eyes, we hypothesize that the sub-population of TM cells that contain smooth muscle actin will also decline with age. We also hypothesize that a greater loss of these cells will be observed in glaucomatous eyes than in nonglaucomatous eyes of the same age. In the present study the ICA of 17 glaucomatous and eight nonglaucomatous eyes were examined for the presence of smA-containing TM cells.
Five-micron sagittal sections of each whole globe were immunolocalized for smooth muscle actin. Positive and negative controls were performed concomitantly.
Labeling was observed in the meshwork of 10 out of the 17 glaucomatous eyes, distributed across all of the age groups represented, including eyes with primary and secondary glaucoma. Smooth muscle actin labeling was observed in the TM of 7 out of 14 eyes with closed-angle glaucoma. Positive immunoreaction was observed in 3/3 eyes with open ICAs. Labeling of smooth muscle actin was observed in the anterior part of the meshwork in only 4 of the 17 glaucomatous eyes, each having had secondary glaucoma. There were no eyes in which label was observed exclusively in the anterior portion of the meshwork. Labeling was most consistently observed in the outer, posterior uveal TM and the inner, posterior corneoscleral TM. All of the eight nonglaucomatous eyes showed greater labeling in both area and intensity than the glaucomatous eyes of the same age.
It was concluded that smooth muscle actin-cell loss is associated with age in canine eyes and that this loss is more severe in glaucomatous eyes.
最近有研究表明，犬眼虹膜角膜角（ICA）内的小梁网（TM）细胞含有平滑肌肌动蛋白（smA）并具有收缩能力，这可能会改变房水流出。由于已发现青光眼犬眼小梁网细胞数量少于年龄匹配的非青光眼犬眼，我们推测含有平滑肌肌动蛋白的TM细胞亚群也会随年龄减少。我们还推测，与同年龄的非青光眼犬眼相比，青光眼犬眼中这些细胞的损失会更大。在本研究中，对17只青光眼犬眼和8只非青光眼犬眼的ICA进行检查，以确定是否存在含smA的TM细胞。
对每个完整眼球的5微米矢状切片进行平滑肌肌动蛋白免疫定位。同时进行阳性和阴性对照。
在17只青光眼犬眼中，有10只的小梁网观察到标记，分布在所有代表的年龄组中，包括原发性和继发性青光眼的犬眼。在14只闭角型青光眼犬眼中，有7只的TM观察到平滑肌肌动蛋白标记。在3只开放ICA的犬眼中观察到阳性免疫反应。在17只青光眼犬眼中，只有4只继发性青光眼犬眼的小梁网前部观察到平滑肌肌动蛋白标记。没有一只犬眼的标记仅在小梁网前部观察到。标记最一致地出现在外层后葡萄膜TM和内层后角膜巩膜TM。所有8只非青光眼犬眼在面积和强度上的标记均比同年龄的青光眼犬眼更强。
得出的结论是，犬眼中平滑肌肌动蛋白细胞的损失与年龄有关，且这种损失在青光眼犬眼中更为严重。
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