| OBJECTIVE Diabetic retinopathy(DR) is one of the most common and sever capillary of diabetes and the reflect of diabetic metabolic disorder, endocrinium and damage of hematological system in retina. One of the central pathological changes is the adherency and aggregation of blood leucocyte and retina micrangium endotheliocyte in it' s occurrence and development, although DR has complicated pathogenesy and is the result of multiple factors synergy. Among all adhesion molecules secreted by endotheliocyte, intercellular adhesion molecule-1(ICAM-1) and vascular cell adhesion molecule-1(VCAM-1) have considerable effect on the occurrence and development of diabetic retinopathy.Peroxisome Proli-ferator-activated receptor PPAR-a and PPAR-y belong to the member of nuclear receptor superfamily, according to the investigation: activation of PPARs may restrain the expression of adhesion molecules. Cilostazol is one of the inhibitors of phosphodiesterase III with significant effect of blood vessel expansion and platelet aggregation inhibition. Currently, Nomura found that cilostazol can inhibit the expression of adhesion molecules,but the mechanisms are little understood.In this study, the Sprague Dawley(SD)rat diabetic model was made by intraperitoneal injection of streptozocin(STZ). Then we observed the changes of blood glucose(BG), hemoglobin Alc(HbAlc)and the expression of ICAM-1 >VCAM-K PPAR-a and PPAR-Y in the retina of the diabetes rat. And to explore the mechanism of cilostazol repressing the expression ofadhesion molecules in levels of mRNA and protein.METHODS Diabetes was induced in male SD rats( 200-220g) by injection of streptozotocin(STZ, 55mg ? kg"') after fasting overnight. Normal control animals received citrate buffer ( n = 9, NC). Diabetes was diagnosed based on blood glucose concentration ( higher than 16. 7mmol ? L"') when STZ-treated rats were at 72 hours. Diabetic rats were divided randomly into four groups: diabetic control group(n = 12, DM) ; high-dose of cilostazol(n = 10, HC) and low-dose of cilostazol(n = 12, LC) ;diabetic group treated with insulin(n - 8, PZI). After treating with 12 weeks, all animals were sacrificed. The following parameters were measured: body weight, fasting blood glucose concentrations, HbAlc. ICAM-1 > VCAM-1 and PPAR- Y protein expression were detected by western- blot, the mRNA level of these two AMs and PPAR- a , PPAR- y were observed by RT-PCR and real-time PCR method.RESULTS (1) The levels of BG in DM group were higher than that in NC group (p<0. 01). The levels of BG in HC group and LC group were not decreased significantly. There was no difference in the levels of BG between NC group and PZI group. (2) The contents of HbAlc in DM group were higher than those in NC group (p<0.01). Compared with the DM group, only insulin had significant effect on the HbAlc and made it down. (3) Morphological observation of retina with the microscope : the structure of the normal rat retina was divided into 10 layers , each layer arranged in regularity; the hierarchical structure in retina of DM rats was loosened obviously . ganglionic layer of retina and inner nuclear layer edema and isolation between the outer and the inner nuclear layer .cilostazol and insulin improved the pathological change of retina in different degree. (4) Morphological observation of pancreas: in normal rats, many pancreatic islets were observed, and the distinct structure of leaflet. In other groups the number of pancreatic islets very few, remnantpancreas islets were atrophy. (5)the analysis of mRNA semi-quantity: compared with NC, the expression of ICAM-1 and VCAM-1 in DM group enhanced significant, cilostazol depressed the expression of adhesion molecules notably;In DM group, the expression of PPAR-a , PPAR- y were degraded significant, cilostazol ameliorated the expression of PPAR-a N PPAR-Y , the result was consistent to real-time PCR. (6) Western-blot:there expressed adhesion molecules in each group. Compared with NC,adhesion molecules increasing expressed in DM group. After treatment with cilostazol, the expressed of adhesion molecules depressed significantly. But the result of PPAR-y reversed .CONCLUSIONS In STZ induced SD diabetic rats, the expression of ICAM-1 and VCAM-1 increased in the retina and the expression of PPAR-a ^ PPAR- y decreased reversely, not onlt mRNA conten but also protein level;cilostazol repressed the expression of ICAM-1 and VCAM-1,and increased the expression of PPAR- a ? PPAR- y ;The mechanism of cilostazol depressing adhesion molecules expression was probably via up-regulating PPAR- a N PPAR- y o...
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