Relevant Between 12-Lipoxygenase And Diabetic Retinopathy

Diabetic retinopathy(DR) is one of the most common retinal vascular diseases. Many recent studies support the hypothesis that inflammatory insults to the retina play an important role in development of the early stages of DR. Lipoxygenases are regulators of chronic inflamation and oxidative stress generation.12-Lipoxygenase(12-LO) is a member of lipoxygenases family which can oxygenate polyenoic fatty acids to the form of 12-hydroxyeicosatetraenoic acid (12-HETE).12-HETE can upregulated the level of ANGⅡ, induce leukocyte/endothelial interaction, participate the leukostasis, play a role in the degeneration of retinal capillaries. All of these changes are major processes involved in the pathogenesis of diabetic retinopathy. The accumulation of 12-HETE could generate large amount of reactive oxygen species, which can leading to chronic oxidative stress. And oxidative stress plays an important role in vascular and neuronal injury associated with DR. The latest research shows that 12-LO plays a role in the pathogenesis of retinal neovascularization via disrupting the normal balance between VEGF and PEDF in retina.However, the specific role of 12-LO in diabetic retinopathy has not yet been elucidated. Therefore, in this paper, we will compare the expression of 12-lipoxygenase in the rat retinas of DR with the normal group.Methods:1. Access the animal models20 adult male Wistar rats were carried out intra-abdominal injection of STZ of 55mg/kg weight for 5 days. After injection 30 min, the rats were allowed to resume eating. Then we extracted tail vein blood for glucose measurement in the 6th days, the 1st week, the 4th week, the 2nd month, the 3rd month, the 4th month, the 5th month after injection. The test method was enzymatic glucose test. The blood glucose was more than 13.9 mmol/L and less than 25mmol/L which indicate the successful establishment of Type II diabetes rat model. At the same time the remaining animals for the normal control group(10).2. Obtaining samplesIn the end of the 5th months ater treatment in rats, we test the blood glucose and body weight, then ether anesthesia, and sacrificed them, removed the eye globes gently.Observation of the lens, iris changes, open up the eye along the rear 0.5mm of corneoscleral junction, careful observation the morphological changes of the retina under a microscope, gently peel off the retina. Remove the retinas to the EP tube by adding 700ul Trizol, placed in-80℃liquid nitrogen refrigerator.3. Detection the expression of 12-LO in retinasApplication of isopropyl alcohol to extraction of retinal mRNA, synthesized cDNA under the action of the reverse transcriptase, with cDNA as a template for polymerase chain reaction, get the PCR products to electrophoresis, and use gel imaging system for quantitative analysis.4. Statistical analysisMeasurement data was performed by using mean±standard deviation (x±s),using SPSS 17.0 software analysis,groups compared with the single-factor analysis of variance,P<0.05 for the difference between statistical significance.ResultsAccording to modeling results, the experimental group were divided into diabetic group and blood glucose recovery group. Diabetic rats daily water intake and urine output was higher than the normal group, fur became dull and matt, the general state were poor. The blood glucose were significantly higher and the weight were significantly lower than the normal group. The result was significant difference (P<0.01). The incidence of complicated cataract in diabetic rats is 100%, some rats exhibited iris neovascularization, peripheral retina and in front of the optic disc neovascularization. The relative expression levels of the normal rat retina 12-LOmRNA is 1.17±0.17, diabetic group 1.96±0.28, blood glucose recovery group is 1.64±0.33. The difference between the experimental group and normal group is significant, blood glucose recovery group is decreased slightly compared with the diabetes rat group, but the difference is not obviously.ConclusionsSTZ can effectively induced diabetic cataract and diabetic retinopathy.5 months rat model after treating with STZ can induce changes of proliferative DR. 12-LO expression in STZ-induced DR rats were significantly increased, and the blood glucose returned to normal had no significant effect on the 12-LO expression.