HDAC6 and type 1 diabetes mellitus: Based on this evidence, we assessed the effects of diabetes on HDAC6 retinal expression and activity in human and experimental DR and we investigated the molecular mechanisms involved in this process in a rat model of type 1 diabetes (streptozotocin-induced diabetic rat = STZ-rat) and in cultures of human retinal microvascular endothelial cells exposed to glucidic stress.