Diabetes, Vol 38, Issue 7 854-860, Copyright © 1989 by American Diabetes Association
Capillary basement membrane thickness and capillary density in sedentary and trained obese Zucker rats
JM Lash, WM Sherman and RL Hamlin
Exercise Science Laboratory, School of Health, Physical Education and Recreation, Ohio State University, Columbus 43210-1284.
The purpose of this study was to determine whether the obese Zucker rat
(OZR) develops diabeteslike peripheral vascular disease and evaluate the
effects of exercise training (treadmill running, 15 m/min, 17% grade, 60
min/day, 5 days/wk, for 6 or 12 wk) on skeletal muscle vascular disease.
Capillary density (CD) and capillary basement membrane (CBM) thickness were
measured in the plantar muscle of sedentary and trained OZR and sedentary
lean Zucker rats (LZRs). At 11 wk old, when profoundly obese,
hyperinsulinemic, and insulin resistant, OZRs had lower CD and thicker CBM
than LZRs. These characteristics are consistent with the expression of
human diabetic microangiopathy and imply altered diffusion capacity due to
increased diffusion distance and changes in the capillary wall. Between 11
and 18 wk of age, OZRs became hyperglycemic. No age-related changes in CD
were observed in lean or obese animals, and OZRs had lower CDs than LZRs at
18 wk of age. CBM thickness decreased from 11 to 18 wk of age in both lean
and obese animals, but the decline was proportionally greater in OZRs, and
the CBM of obese animals was only slightly thicker than in lean 18-wk-old
animals. Exercise training did not alter CD or CBM thickness in 11-wk-old
animals. In contrast, training for 6 or 12 wk increased both CD and CBM
thickness in 18-wk-old animals, normalizing CD but further increasing CBM
thickness relative to LZRs. Correlational analysis revealed that CBM
thickness is related to basal insulin concentration (r = .29, P less than
.05) but not to basal glucose (r = .12, P greater than .05).(ABSTRACT
TRUNCATED AT 250 WORDS)