Degeneration of retinal neuronal processes and pigment epithelium in the early stage of the streptozotocin-diabetic rats.
Early pathological and electro-physiological changes of the retina in the streptozotocin (STZ)-diabetic rats were investigated through optical and electron microscopy in two strains and electro-retinography in one strain. In Sprague-Dawley (SD) rats I month after the onset of diabetes, the thickness of the inner plexiform layer (IPL) and photoreceptor segment layer (PSL) was significantly reduced by 9.9% and 18.9%, respectively (P < 0.01, P < 0.05). In Brown-Norway (BN) rats STZ-diabetic for 1 month, the thickness of the IPL was also significantly reduced by 15.7% (P < 0.05). Cytochemical study using peanut agglutinin (PNA), a lectin binding selectively to the cone photoreceptor-associated domains of the inter-photoreceptor matrix, revealed a marked reduction in intensity, number and length of the PNA-binding cone photoreceptors. Electron microscopy showed deepened hollows in the basal infoldings of the retinal pigment epithelium (RPE) of STZ-rats diabetic for 1 month and large concavities into the cytoplasm in STZ-rats diabetic for 6 months. Blood vessels in the retina and choroid were unremarkable. Single-flash electro-retinogram revealed a reduction in the amplitudes of alpha- and beta-waves of electro-retinogram (ERG) of 1 month STZ BN rats (P < 0.05). These findings indicate that the degeneration of rods/cones in the PSL and RPE are the most prominent pathological alteration sites in the early stage of diabetic rats.
Aizu
Yoshinori
Y
Research & Development Center, BML, Kawagoe City, Saitama, Japan.
Oyanagi
Kiyomitsu
K
Hu
Jianguo
J
Nakagawa
Hachiro
H
D000818:Animals; D002829:Choroid / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D004596:Electroretinography; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D009410:Nerve Degeneration / Q000473:pathology*; D019887:Peanut Agglutinin / Q000378:metabolism; D010857:Pigment Epithelium of Eye / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000378:metabolism / Q000503:physiopathology* / Q000648:ultrastructure*; D013997:Time Factors
D005904:Glial Fibrillary Acidic Protein; D019887:Peanut Agglutinin