目的：探讨二十二碳六烯酸(DHA)玻璃体注射对年龄相关性黄斑变性(ARMD)大鼠光感受器细胞凋亡和磷脂酰肌醇-3-激酶/丝苏氨酸蛋白激酶(PI3K/Akt)通路的影响。

方法：大鼠随机分为空白对照组、模型组、低剂量DHA组(L-DHA组)、中剂量DHA组(M-DHA组)和高剂量DHA组(H-DHA组)。采用光损伤法建立干性ARMD大鼠模型。HE染色观察视网膜病理变化，TUNEL法检测视网膜细胞凋亡情况，透射电镜观察视网膜神经节细胞超微结构，酶联免疫吸附法测定视网膜组织TNF-α和IL-6水平，Western Blot检测视网膜组织p-PI3K、p-Akt、Bax、Bcl-2、p-NF-κBp65和cleved-caspase-3蛋白表达。

结果：与空白对照组比较，模型组大鼠视网膜总厚度、外核层和内核层厚度、视网膜组织p-PI3K、p-Akt和Bcl-2蛋白表达均降低(P<0.05)，神经节细胞层和外核层细胞凋亡指数、视网膜组织TNF-α和IL-6水平、Bax、p-NF-κBp65和cleved-caspase-3蛋白表达均升高(P<0.05)。与模型组比较，M-DHA组和H-DHA组大鼠视网膜总厚度、外核层和内核层厚度、视网膜组织p-PI3K、p-Akt和Bcl-2蛋白表达均升高(P<0.05)，神经节细胞层和外核层细胞凋亡指数、视网膜组织TNF-α和IL-6水平、Bax、p-NF-κBp65和cleved-caspase-3蛋白表达均降低(P<0.05)。

结论：DHA可能通过激活PI3K/Akt通路抑制ARMD大鼠光感受器细胞凋亡。

METHODS: The rats were randomly divided into blank control group, model group, low dose DHA group(L-DHA group), medium dose DHA group(M-DHA group)and high dose DHA group(H-DHA group). The rat model of dry ARMD was established by light injury. He staining was used to observe the pathological changes of retina, TUNEL method to detect the apoptosis of retinal cells, transmission electron microscopy to observe the ultrastructure of retinal ganglion cells, enzyme-linked immunosorbent assay to detect the levels of TNF - α and IL-6 in retina, Western blot to detect the expression of p-PI3K, p-Akt, Bax, Bcl-2, p-NF-κBp65 and cleved-caspase-3 protein in retina.

RESULTS: Compared with the blank control group, the total thickness of retina, the thickness of outer nuclear layer and inner nuclear layer, the expression of p-PI3K, p-Akt and Bcl-2 protein in the retina of the model group decreased(P<0.05), the apoptosis index in the ganglion cell layer and outer nuclear layer, the level of TNF-α and IL-6 in the retina, the expression of Bax, p-NF-κBp65 and cleared caspase-3 protein increased(P<0.05). Compared with the model group, the total thickness of retina, the thickness of outer nuclear layer and inner nuclear layer, the expression of p-PI3K, p-Akt and Bcl-2 protein in retina increased in M-DHA group and H-DHA group(P<0.05), the apoptosis index in ganglion cell layer and outer nuclear layer, TNF-α and IL-6 levels in retina, Bax, p-NF-κBp65 and cleved caspase-3 protein expression decreased(P<0.05).

CONCLUSION: DHA may inhibit photoreceptor apoptosis by activating PI3K /Akt pathway.