Insulin inhibits and oral sucrose increases neointimal growth after arterial injury in rats.
OBJECTIVE
In our previous studies, rats on insulin treatment (5 U/day) and oral glucose to avoid hypoglycemia had reduced neointimal growth after arterial injury. However, plasma glucose in the insulin-treated rats was lower than normal and the effect of oral glucose remained undetermined. In this study, the effects of normoglycemic hyperinsulinemia and oral glucose or sucrose were investigated in the same model.


METHODS
Rats were divided into 6 groups: (1) control implants and tap water; (2) insulin implants (5 U/day) and oral glucose + i.p. glucose to avoid any glucose lowering; (3) insulin implants (4 U/day) and oral glucose; (4) insulin implants (4 U/day) and oral sucrose; (5) control implants and oral glucose, and (6) control implants and oral sucrose.


RESULTS
Insulin treatment at both doses reduced neointimal area (p < 0.001) 14 days after injury in rats receiving oral glucose but not in those receiving oral sucrose. Oral glucose, without insulin, had no effect on neointimal formation, whereas oral sucrose increased neointimal growth (p < 0.05). Oral sucrose (p < 0.05) but not oral glucose decreased insulin sensitivity measured with hyperinsulinemic clamps.


CONCLUSIONS
(1) Insulin decreases neointimal growth after arterial injury independent of glucose-lowering or oral glucose administration and (2) oral sucrose per se affects neointimal growth.
Breen
Danna M
DM
Department of Physiology, University of Toronto, Toronto, Ont., Canada.
Dhaliwall
Jiwanjeet K
JK
Chan
Kalam K
KK
Guo
June
J
Lam
Loretta
L
Bendeck
Michelle P
MP
Giacca
Adria
A
D000284:Administration, Oral; D000800:Angioplasty, Balloon / Q000009:adverse effects; D000818:Animals; D020212:Carotid Artery Injuries / Q000473:pathology*; D050171:Dyslipidemias / Q000378:metabolism / Q000473:pathology; D005215:Fasting; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D008297:Male; D051381:Rats; D013395:Sucrose / Q000008:administration & dosage / Q000494:pharmacology*; D017539:Tunica Intima / Q000473:pathology*; D017540:Tunica Media / Q000473:pathology
D007328:Insulin; D013395:Sucrose; D005947:Glucose