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.