FUNCTION OF AQUAPORIN OF RETINAL MUELLER CELLS IN RETINAL EDEMA AND DETACH MENT

水通道蛋白（Aquaporins，AQP）是一种水通道蛋白，广泛分布于眼部。AQP 4存在于视网膜Mueller细胞中，可能与视网膜下液的吸收和/或视网膜水肿有关。免疫电镜显示，AQP 4存在于Mueller细胞的质膜上，不易造成实验性视网膜水肿或视网膜脱离。在这项研究中，我们进行了视网膜激光光凝和水肿周围的激光烧伤。免疫组化结果显示，在激光光凝后的视网膜水肿中，水肿周围AQP 4的表达增加。内膜剥除有利于黄斑裂孔的闭合和黄斑水肿的吸收，但有时术后较长时间仍会出现黄斑囊样水肿。对手术切除的ILM进行了ILM剥离和AQP 4免疫组织化学染色，发现手术切除的ILM内表面存在与AQP 4位置相对应的胶体金，提示Mueller细胞中的AQP 4可能在视网膜水肿或视网膜下液的吸收中起作用，Mueller细胞的损伤可能引起黄斑囊样水肿。

Aquaporins (AQPs) are water channel proteins and distribute widely in the eye. AQPs are reported to exist in Mueller cells and may play a role in the absorption of subretinal fluid and/or retinal edema.We demonstrated that AQP 4 exists in the retinal Mueller cells by using light microscopic immunohistochemistry. Furthermore, AQP 4 was revealed to exist in the plasma membrane of Mueller cells by immunoelectron microscopy.It is difficult to make the experimental retinal edema or retinal detachment in the rat eye. In this study, we performed retinal laser photocoagulation and edema occurred around the laser burns. In the retinal edema after laser photocoagulation, the expression of AQP 4 was increased around the retinal edema by immunohistochemistry.Internal limiting membrane (ILM) peeling was widely used in recent surgery of retinal macular hole or macular edema. ILM peeling facilitated the closure of macular hole and absorption of macular edema, but sometimes cystoid macular edema occurred for long time after surgery. We performed the ILM peeling and the immunohistochemistry for AQP 4 in surgically removed ILM.Colloidal golds which corresponded to AQP 4 location existed in the inner surface of surgically removed ILM.These results suggest AQP 4 in Mueller cells may play a role in absorption of retinal edema or subretinal fluid, and the damage of Mueller cells may cause the cystoid macular edema.