[Architectural changes with duration of hypertension in the retinal capillary network of spontaneously hypertensive...

Narrowing of the retinal artery in hypertension has been considered as an indicator of peripheral vascular resistance, which is largely caused by contraction or narrowness of retinal arterioles. But the relationship between peripheral vascular resistance and the retinal capillary network is little known. To study this relationship, three groups of age-matched rats were used: normotensive Wistar-Kyoto rats 6, 15, and 20 weeks, of age, and spontaneously hypertensive rats (stroke-resistant spontaneously hypertensive rats and stroke-prone spontaneously hypertensive rats) 6, 15, and 20 weeks of age. The size of the retinal capillary network in a given area was measured in these groups. There was no difference in the size of the retinal capillary network at any point in the Wistar-Kyoto rats. There was no difference in the size of the retinal capillary network among the three groups at 6 weeks of age, but there was a significant increase in spontaneously hypertensive rats at 15 weeks. We could not measure the size of the retinal capillary network in part of the spontaneously hypertensive rats at 20 weeks. These results suggested that retinal capillary network becomes larger with duration of hypertension and it acts to increase peripheral vascular resistance.