AUGMENTED RETINAL ENDOTHELIN-1 ENDOTHELIN-3 ENDOTHELIN(A) AND ENDOTHELIN(B) GENE-EXPRESSION IN CHRONIC DIABETES

Purpose. Endothelins (ETs) belong to a family of vasoactive peptides i mplicated in several disorders of the microvasculature. In the present study, we investigated ET-1 and ET-3 peptide mRNAs and ETA, ETB recep tor mRNAs in the retina of diabetic BB/W rats and age-matched, non-dia betic control animals, following six months of diabetes. Methods. Tota l mRNA was extracted from each retina and was subjected to reverse tra nscriptase polymerase chain reaction for ET-1, ET-3, ETA and ETB. Simu ltaneously, beta-globin was amplified and used as a housekeeping gene. The products were analyzed on agarose gels and the specificity of the amplification was established by hybridization with amplification-spe cific biotinylated oligoprobes. For quantification, the products from the linear phase of amplification were subjected to serial dilution sl ot-blot hybridization and densitometry. Results. ETs and their recepto r mRNA expressions were present in the retina. Retinas from the diabet ic animals showed significant increases in ET-1, ET-3 ETA, ETB mRNA ex pressions compared to those from control rats. Conclusions. These find ings indicate that retinal ET-1, ET-3, ETA and ETB mRNA expression is increased in the chronically diabetic BB/W rat. Augmented gene express ion of ETs and their receptors potentially may be of importance in the pathogenesis of retinal microangiopathy in diabetes.