The Expression Of FAS And E-FABP In The Retina Of Alloxan Induce Diabetic SD Rats

ObjectiveDiabetic retinopathy is the most common and serious complication of diabetes. For several decades the pathogenesis of diabetic retinopathy has been an important object. Investigators proposed many meritorious assumptions and hypotheses through experiment studies. While, the disease mechanisms remain no definitive conclusion. Insulin is the principal hormone can regulate the fat synthesis. On account of direct (type 1 diabetes mellitus) or indirect (type 2 diabetes mellitus) insulin deficiency . the sufferers of diabetes mellitus inevitably suffer disorder of lipids metabolism. Fatty acid synthase (FAS) is a key enzyme in the lipogenic pathway that catalyzes all the reactions in the conversion of acetyl-CoA and malonyl-CoA to palmiticacid. Fatty acid binding-proteins (FABPs) serve as intracellular acceptors of FAs, and they may also have an effect on ligand- dependent transactivation of correlative genes. FABPs have many subtypes. They have tissue specificity. In retinal, epidermal-FABP has expression. This experiment objective is to observe the expression of FAS and E-FABP in the retina of the non-diabetic and diabetic rat with the methods of semi-quantitative reverse transcription -polymerase chain reaction (RT-PCR) and immunohistochemical method. And discuss the role of FAS and E-FABP in the diabetic retinopathy pathogenesis.Method1. Injecting Alloxan was induced the diabetic rat model. The control rats received the same volume of Sodium Chloride buffer. 12 weeks after, the control and treated rats were sacrificed to analysis.2. FAS and E-FABP mRNA expression abundance in the retinas of the control and the 12 weeks diabetic rats were measured by RT-PCR.3. FAS and E-FABP expression in the retinas of the control and the 12 weeks diabetic rats were detected with the immunohisto-chemcal method.Results1. We had established taye 1 diabetes mellitus models successfully. Almost all models occurred diabetic typical symptoms: polydipsia, polyphagia, urorrhagia, and athrepsy. 12 weeks after, we obtained 8 diabetic model rats in all.2. Through semi-quantitative RT-PCR experiment, we observed the retinal FAS mRNA expression abundance of the 12 weeks diabetic rats were remarkable increased than the control rats (P< 0. 01) . The mRNA expression abundance of E-FABP had no statistical difference.3. Through the immunohistochemcal method, the FAS positive stains were mainly observed in the cone and rod inner segment. There had some positive stain cells in the outer plexiform layer (OPL), inner nuclear layer (INL), internal plexiform layer (IPL) and nerve fiber layer (NFL) . In the retina of diabetic rats, the FAS positive stain cells and the stain extent significantly increased. E-FABP positive stains were mainly observed in outer nuclear layer (ONL), OPL, INL, IPL, and ganglion cell layer (GCL). There had no significant difference between experimental group and control group.ConclusionThe increasing expression of FAS in the diabetic model rats suggest FAS maybe plays an important role in the genesis and development of diabetic retinopathy through abnormal adipose metabolism pathway. Expression of E-FABP is almost not change because E-FABP is been regulated by intracellular and plasma fatty acid simultaneous.