Retinopathy in diabetic (KKA gamma) mice: diabetic microvascular changes to the retina in KKA gamma mice revealed by light and electron microscopy.

摘要

Pericytic changes in the retinal vessels of diabetic (KKA gamma) and control (C57BL) mice were studied by light and electron microscopy. An improved histochemical technique for alkaline phosphatase was used in the light microscopic study. In the control mice, a continuous pathway was identified extending from the retinal arterioles, via the superficial and deep retinal capillaries, to the retinal venules. The deep retinal capillaries formed networks and were localized within the deeper retinal layers; the retinal arterioles, superficial capillaries, and venules were present in the nerve fiber layer. Examination of KKA gamma mice, aged 16 to 28 weeks, revealed engorgement of the arterioles, hypertrophy of the pericytes (which contained numerous actin filaments) within the superficial retinal capillaries, and narrowing of the deep retinal capillaries. These microvascular changes indicate retinal hyperperfusion, local hypertension of the superficial retinal capillaries, adaptive hyperfunctional changes inthe pericytes of these capillaries, and ischemia of the deep retinal capillaries. The pericytic changes observed in the diabetic capillaries contrasted sharply with previous reports; an explanation for this variance is suggested.