Purpose. Capillary basement membrame thickening (CBMT) has been shown to occur in several tissues in human and experimental diabetes. However a comparison of the retinal and renal ultrastructural effects of diabetes and their response to intervention has not been performed. This study has investigated the effects of aminoguanidine (AG) on retinal and glomerular CBMT in the streptozotocin STZ) diabetic rat. Methods. Three groups of male Sprague Dawley rats, aged 6-8 weeks, were studied; Controls (C) were injected with vehicle, diabetic (D) received STZ, 45mg/kg i.v. and diabetic + AG (D + AG) received STZ as above and AG lg/L of drinking water. At 8 months, the rats were anaesthetized with Nembutal and the eyes and kidneys were perfusion fixed in situ with glutaraldehyde. Electron micrographs were taken of the outer plexiform layer capillaries of retina and CBMT was measured using the average basement membrane method of Siperstein, at 6-25 sites in at least 16 vessels per eye. In another set of rats, glomerular CBMT was measured by the orthogonal intercept method in two glomeruli per rat, using 50 measurements per glomerulus. Results. Plasma glucose levels were similar in both diabetic groups (C 8.8 ± 0.4, D 35.0 ± 2.1, D + AG 31.4 ± 3.7mM). CBMT (nm, mean ± SEM) is shown below, p < 0.05 D vs C*, p < 0.05 D + AG vs D† Control(n) Diabetic(n) Diabetic + AG(n) Retina 97 ± 5 (7) 115 ± 5 (6)* 102 ± 4 (12)† Glomerulus 163 ± 3 (17) 187 ± 8 (25)* 189 ± 3 (23) Conclusions: CBMT increased by 15-20% in both retina and glomerulus in diabetic rats. However AG prevented diabetes-related increases in CBMT only in the retina, suggesting that the effects of AG may be to some degree tissue-specific in the eye and the kidney.
|Journal||Investigative Ophthalmology and Visual Science|
|Publication status||Published - 15 Feb 1996|