Alterations in expression of angiopoietins and the Tie-2 receptorin the retina of streptozotocin induced diabetic rats

[摘要] Purpose: The angiopoietin (Ang)/Tie-2 system may play a role invascular integrity and angiogenesis. In this study, we investigatedalterations of the gene expression of Ang-1 and Ang-2 in the retinas ofstreptozotocin (STZ) induced diabetic rats.Methods: In situ hybridization, reverse transcriptase polymerasechain reaction (RT-PCR) and western blot analyses were performed todetermine the mRNA and protein content for Ang-1 and Ang-2 and the Tie2receptor in the retinas of STZ diabetic and age matched control rats.Results: Using in situ hybridization analysis, Ang-1, Ang-2, andTie2 mRNA expression was observed in the ganglion cell layer (GCL) andthe inner nuclear layer (INL). While Ang-2 mRNA expression did notchanged after 2 weeks, 1 month, or 3 months of STZ induced diabetes, itwas increased in the GCL and slightly elevated in the INL after 6 monthsof diabetes. In contrast, Ang-1 and Tie2 mRNA expression was stable atevery timepoint during 6 months of STZ induced diabetes. RT-PCR andwestern blot analyses confirmed the increase of Ang-2 expression after 6months of diabetes. Furthermore, double staining of alpha-smooth muscleactin (αSMA) and Ang-2 mRNA demonstrated that the SMA positivecells surrounding Ang-2-expressing cells were decreased in the GCL.Conclusions: Diabetes increases Ang-2 expression in the GCLaccompanied by a reduction of αSMA positive perivascular cells.These changes may suggest a role for Ang-2 in the mechanism of pericyteloss in diabetic retinopathy.

[学科分类] 生物化学/生物物理