TTX对糖尿病大鼠机械刺激诱发C纤维高频放电的抑制作用

目的:探讨糖尿病大鼠机械刺激诱发C纤维高频放电的机制。方法:24只SD大鼠随机分为对照组和模型组,模型组腹腔注射70 mg/kg链脲菌素制作糖尿病模型,对照组腹腔注射相同剂量的生理盐水。造模前48 h、造模后48 h和4周分别取尾静脉血测血糖浓度;造模前3 d,造模后3、7、14、21、28 d通过刺激后爪,采用vonFrey法测定大鼠50%机械缩爪阈值(PWT)。取造模后4周的大鼠,分离尾神经,测定传导速度以确定纤维类型,并给予60 s的阈上(100 g)机械刺激,记录单根C纤维的放电。在糖尿病大鼠的尾巴上暴露尾神经,给予100nmol/L的TTX 10 min后施加60 s阈上(100 g)机械刺激,观察并记录其放电。结果:造模后48 h模型组(n=12)随机血糖浓度高于16.7 mmol/L的比率为91.7%,与对照组(n=12)比较,模型组在48 h、4周时血糖明显增高;造模后3周模型组PWT明显低于对照组(P<0.05);糖尿病组大鼠C纤维对60 s阈上(100 g)机械刺激诱发的放电数明显高于对照组;加100 nmol/L低浓度的TTX后,糖尿病大鼠中C纤维对机械刺激的放电数明显减少(P<0.01)。结论:低浓度的TTX可以抑制糖尿病大鼠机械诱发的C纤维高频放电。

TTX inhibited the high frequency firing from C-fiber evoked by mechanical stimulation in diabetic rats

Objective:To investigate the mechanism of high frequency firing from C-fiber evoked by mechanical stimulation in diabetic rats.Methods:Twenty-four SD rats were randomly divided into control group and diabetic group.Rats in diabetic group were performed intraperitoneally streptozotocin(STZ) injection at a dose of 70 mg/kg,while the same volume of saline was injected in control rats.Blood samples from tail vein were collected to determine the concentration of blood glucose at 48 h,and 4 weeks after STZ or sal...