Ma. Cotter et al., EFFECTS OF NATURAL FREE-RADICAL SCAVENGERS ON PERIPHERAL-NERVE AND NEUROVASCULAR FUNCTION IN DIABETIC RATS, Diabetologia, 38(11), 1995, pp. 1285-1294
Citations number
54
Categorie Soggetti
Endocrynology & Metabolism","Medicine, General & Internal
Increased generation of reactive oxygen species, coupled with impaired
endogenous scavenging mechanisms, plays a prominent role in the aetio
logy of neurovascular abnormalities in experimental diabetes mellitus.
We examined the efficacy of the natural anti-oxidants vitamins C, E a
nd beta-carotene in preventing nerve conduction and nutritive blood fl
ow deficits in streptozotocin-diabetic rats. One month of diabetes cau
sed a 19.1% reduction in sciatic motor conduction velocity (p < 0.001)
. This was approximately prevented 80-90% by high-dose (1000 mg . kg(-
1). day(-1)) vitamin E and beta-carotene treatments (p < 0.001). Vitam
in C had lesser effects; the maximum protection found for motor conduc
tion velocity was 36% using a dose of 150 mg . kg(-1). day(-1) (p < 0.
001). High dose (500 mg . kg(-)1 . day(-1)) vitamin C had a lesser eff
ect on conduction than intermediate doses. Joint vitamin C and lower d
ose (500 mg . kg(-1). day(-1)) vitamin E treatment had a predominantly
additive preventive effect against nerve dysfunction. Resistance to h
ypoxic conduction failure for sciatic nerve in vitro was markedly incr
eased by diabetes and this remained relatively unaffected by treatment
. Sciatic nutritive endoneurial blood flow, measured using microelectr
ode polarography and hydrogen clearance, was reduced 46.1% by 1 month
of diabetes (p < 0.001). This was prevented to the extent of 87 %, 36
% and 98 % by vitamins E, C and beta-carotene, respectively (p < 0.01)
. These data emphasize the role of oxidative stress in the development
of early neurovascular changes in experimental diabetes and show that
naturally available scavengers have a neuroprotective action.