| BackgroundThe cataract ,caused by the lens opacity, is a kind of eye disease that induces visual disorder and influcnces the visual result. Incidence of diabetic cataract has a upgrade tendency with the increase of the diabetic patients,it has been a hot research topic.ILK (integrin-linked kinase) is a serine/threonine protein kinase,regulates a wide variety of biological processes. ILK is a key element in the regulation of integrin, growth factor and Wnt signaling pathways. ILK can interact directly with the cytoplasmic domain of the beta1 and beta3 integrin subunits and whose kinase activity is modulated by cell-extracellular matrix interactions. ILK is involved in the formation of cystoskeleton,the regulation of cell adhesion,growth,gene expression, differentiation,cell shape change,and ECM assembly. It links integrins to actin cystoskeleton,transduce signal from integrin to ECM and various subcellular components,and from extracellular environment to intracellular signal. Many researches on ILK have been done in the fields of both cancer and kidney fibration. More and more people have noticed that ILK effects the complications in diabetes,many researches on diabetic nephropathy found the expression of ILK higher than normal kidney. High glucose leads to the expression of ILK in the mouse podocytes higher than those in control cells. The elevation of PKB/Akt phosphorylation inhibited the apoptosis induced by high glucose. ILK was also found increasing in retina of diabetic rats.The incidence of diabetic cataract is higher than that of age-related cataract,and the occurrence ages are in advance. The incidence of posterior cataract opacities is also higher than that of age-related cataract. It has been found that ILK is expressed in epithelium cells of rat lens, fiber cells of the mouse lens and epithelium cells of human lens.However,biological function of ILK and its related signaling molecules in diabetic catacter has not been demonstrated. The purpose of this study was to investigate the expression of ILK,α-SMA in the cultured human lens epithelium cell under the condition of high glucose and to gain insight into their roles in the progression of diabetic catacter,and to elucidate the possible regulation of ILK in the diabetic catacter associated with diabetes mellitus.AimTo determine the role of ILk on the human lens epithelial cells cultured with high glucose in vitro.MethodsHuman lens epithelial cell line SRA01/04 was used. The cells were exposed to either 5.5 (normal control),15.5,30.5,or 50.5 mmol/L glucose or 25 mmol/L mannitol + 5.5 mmol/L glucose (mannitol control) for 0,6,12,24,48 and 72 h. The survival and proliferation of the cells were quantified by MTT assay. ILK was cultured in low glucose and the immunoreactivity was examined by immunocytochemistry.The ILK,α-SMA protein expression was analysed with western blotting after exposure to 30.5 mmol/L glucose for 6,24 and 72h. Results1. There was an increase in cell proliferation from 15.5 to 50.5mmol/L of glucose compared with the normal and mannitol controls. The peaks of cell proliferation were in the group of 30.5mmol/L glucose, and at 48 or 72 h exposure.2. Immuocytochemisry analysis showed that ILK immunoreactivity detected idicated ILK distributed in the cytoplasm of the human lens epithelial cells cultured in low glucose in vitro.3. Western blot analysis showed that the ILK protein levels in SRA01/04 cells exposed to 30.5 mmol/L glucose were 1.25 and 1.28 times higher than those in control cells at 6 and 72 h exposure, respectively. High concentration of mannitol did not up regulate the expression of ILK protein. Moreover,the expression levels ofα-SMA protein were increased cultured in 30.5 mmol/L glucose for 6,24 and 72 h. Meanwhile,High concentration of mannitol did not up regulate the expression of ILK andα-SMA protein.ConclusionHigh glucose may induce up-regulation of ILK andα-SMA and increase the cell proliferation in the human lens epithelial cells. These effects are not dependent on the osmotic stress resulting from elevating the concentration of glucose. |
