Study Of The Protective Effects Of Zhou Luo Tong On Diabetic Peripheral Neuropathy And Its Mechanisms

Study of the Protective Effects of Zhou Luo Tong on diabetic peripheral neuropathy and Its MechanismsDiabetic peripheral neuropathy (DPN) is a most common and troublesome complication of diabetes mellitus, leading to the greatest morbidity and mortality and resulting in a huge economic burden for diabetes care. The pathogenesis of DPN has still not been fully explored. There are many hypotheses mainly related to metabolism disorder and vascular dysfunction. Effects of most drugs for DPN are expected to be proved in clinic because of lack of effective treatment for DPN. As a result, there is an urge to develop Chinese medicine for DPN.It has been proved that Zhou Luo Tong (ZLT), a mixed Chinese medicine, had beneficial effects on some symptoms of DPN, for example, limbs paresthesia, numbness and pain. Therefore, the pharmacological effects and mechanisms of ZLT on diabetic peripheral neuropathy were studied under the condition of prevention administration and therapy adminstration from the aspect of metabolism disorder with streptozotocin-induced diabetic(STZ-D) rat and mouse models.Protective effects of ZLT on DPN in STZ-D mice with preventional administration Male ICR mice were rendered diabetic by intraperitoneal injection of streptozotocin. Diabetic and control animals were administrated for 12 weeks.Diabetic mice were high glycosuria level and exhibited reduced body weight compared with the controls after the injection of streptozotocin. The significant effects of ZLT on body weight and glycosuria level on diabetic mice were not found during the experiment.Effects of ZLT on thermal response latency, cool response latency, flinching after paw formalin injection and loading climb times of STZ-D mice were determined.Thermal response latency in diabetic group was shorted at week 2(p<0.01) and was prolonged at week 4, week 8 and week 12(p<0.05, p<0.01, p<0.01, respectively) compared with that in the control group. Thermal response latencies in 1.03g/kg, 0.51 g/kg, 0.26 g/kg ZLT treated diabetic groups at week 8 and 0.51 g/kg, 0.26 g/kg ZLT treated diabetic groups at week 12 were shortened compared with that in vehicle-treated group (p<0.01,p<0.01, p<0.01, respectively and p<0.05, p<0.05, respectively).Cool response latency in diabetic group was not changed significantly at week 2 (p>0.05), but there was a trend to decrease (p<0.1). Cool response latency in diabetic group was increased at week 8 (p<0.05) and the tread was maintained at week 12 (p<0.1). Cool response latency in 1.03g/kg ZLT treated diabetic group was prolonged at week 8 compared with that in vehicle-treated diabetic group.Flinching frequency after injection of formalin into the hind paw was exaggerated after 2 weeks (p<0.05) of diabetes and was decreased after 8 weeks (p<0.01) in vehicle-treated diabetic micecompared with control. Flinching frequency of diabetic mice was not effected by ZLT (p>0.05) during experiment.Loading climb times in vehicle-treated diabetic group were shortened significantly at week 4,week 8 and week 12 (p<0.01, p<0.01, p<0.05, respectively) compared with control. Loading climb times in 0.51 g/kg, 0.26 g/kg ZLT treated diabetic groups were prolonged at week 4, week 8 and week 12 compared with vehicle-treated diabetic group (all p<0.05).Protective effects of ZLT on DPN in STZ-D rats with preventional administration Experiments were performed on adult male and female Wistar rats and diabetes were induced by STZ injected intraperitoneally. Animals were administrated daily for 8 weeks with ZLT or vehicle after diabetes was induced.The body weight of male and female diabetic rat groups were reduced significantly at the 2-,4-,6-,and 8-week after STZ injection compared with the control group(all p<0.01). There were no effect of ZLT on body weight of diabetic rats was found at all time points compared with vehicle-treated diabetic rats (all p>0.05).The average diet quantity and drinking quantity of male and female diabetic rats were increased. No effects of ZLT on the average diet qu...