The effect of long-term supplementation of vitamin C on pulpal blood flow in streptozotocin-induced diabetic rats

To examine the effect of vitamin C on blood flow in diabetic dental pulp, the animal model of streptozotocin (STZ)-induced diabetic rats (i.v. injection of STZ 55 mg/kg BW) was used. Male Sprague-Dawley rats weighing 200-250 g were divided into 3 groups: non-diabetes (CON), diabetes (STZ), and diabetes supplemented by vitamin C (STZ+Vit C). Vitamin C was supplemented by drinking water (1 g/l). At 12 weeks (wks) and 24 wks after the STZ injection, the laser Doppler flow-meter (Model ALF 21, USA) was used to measure pulpal blood flow (PBF) while the animals were anesthetized with sodium pentobarbital (50 mg/kg BW). The experimental results showed that at 12 and 24 wks after the STZ injection, hyperglycemia hypertension and loss of body weight were significantly developed. Simultaneously, decreased plasma vitamin C level was demonstrated significantly in STZ rats. The reduction of pulpal blood flow (PBF) in the lower incisors was observed in STZ rats at both monitored time points. Interestingly, the supplementation of vitamin C for 24 wks restored PBF. In conclusion, the present study demonstrated that long-term supplementation of vitamin C, a natural antioxidant, could markedly prevent the diabetic-induced reduction in PBF.