Abstract
Abstract: :
Purpose: Diacylglycerol (DG) is a second messenger to activate protein kinase C (PKC), which is involved in the signal transduction pathways from various growth factors. Diacylglycerol kinase (DGK) phosphorylates DG, which is degraded into phosphatidic acid (PA), and regulates the intracytoplasmic signal transduction by regulating DG level and inositol–phospholipid turnover. Recent studies have identified that PKC is activated and DG levels increase by hyperglycemia. These mechanisms are speculated to be associated with vascular pathological states in retina, including early stage of diabetic retinopathy (DMR). We observed the protein expression patterns of DGKζ isoforms and cytokines to investigate the clinical significance of DGK during the pathogenesis of diabetic retinopathy. Methods:Retinal specimens from Streptozotocin induced rats (STZ) and Spontaneously Diabetic Torii (SDT) rats (supplied by the courtesy of Torii Pharmaceutical Co., Ltd., Tokyo, Japan) were observed. SD rats were used as the normal control.The expression at the protein levels of DGK isoforms and cytokines (VEGF, IL–6, angiotensin II, TGFß1,2,and PEDF) in the retina were observed immunohistochemically and by Western blotting. Results: The expression patterns and expression levels of DGKζ, VEGF, IL–6 and angiotensin–II changed in either the STZ or the SDT rat retina in comparison with the normal control. The expression of DGKζand IL–6 was mainly detected in the retinal vessels, and angiotensin–II was observed in the vessels and the inner nuclear layer in the diabetic retina. VEGF expression increased in whole layere of the diabetic retina. Conclusions:It is possible that DGKζ and VEGF are involved in the pathogenesis in the early stage of DMR.
Keywords: immunohistochemistry • pathology: experimental • cytokines/chemokines