Abstract
Despite efforts on a wide scope, the exact nature of diabetic retinopathy has remained obscure. In pursuing the pathogenesis of this disease, the retinal blood vessels of congenitally diabetic KK mice were observed histlogically in flat preparations using a trypsin digestion method and electron microscopically.
As controls, non diabetic ICR and DDY mice with similar weight and age were used. Deep staining of arterial branches with PAS stain, dilatation of the vein and protuberance of the mural cell were observed in old KK mice (from 7 to 20 months old).
Electron microscopically, the basement membrane of the capillaries showed thickening. But typical microaneurysms, bleedings or white spots seen in human diabetes were not observed,
In a loaded experiment using three-months KK mice,
1) With ligation of carotid arteries, mural cells showed a trend to decreased in number.
2) Protuberance of mural cells was observed three weeks after injection of alloxan in a dose of 100 mg/Kg.
3) After administration of alloxan and IDPN, proliferation of endthelial cells and diminution of mural cells were noted three weeks after injection.
4) No histological changes were observed following injection of steroid.
5) When a growth hormone was injected, no remarkable electron microscopic findings were obtained.
Electron microscopically, a significant thickening of the basement membrane of the retinal capillaries was observed not only in untreated old KK mice but also in young KK mice treated with alloxan and alloxan plus IDPN.
As a whole, diabetic retinal angiopathy in KK mice was observed but no diabetic retnopiathy as seen in human diabetes was demonstrated.
