Expression of ceramide galactosy transferase in sciatic nerve of rats with diabetic peripheral neuropathy after electroacupuncture at Zusanli and Shenshu points

BACKGROUND： Ceramide galactosyltransferase （CGT） protein and mRNA expression defect can cause the abnormal morphology and slowing conduction velocity of peripheral nerve. Morphologic change and functional disorder of myelin sheath and axon appear when diabetic peripheral neuropathy （DPN） occurs. Whether electroacupuncture at Zusanfi（ST 36） and Shenshu（BL 32） points can enhance the expression of CGT protein and mRNA in the DPN tissue？ OBJECTIVE： To observe the effect of electroacupuncture at Zusanfi and Shenshu points on motor, sensory conduction velocity and CGT mRNA and its protein expression of sciatic nerve in rats with DPN. DESIGN： A randomized and controlled animal experiment SETTING ： Department of Neurology and Central Laboratory, Yueyang Hospital of Traditional Chinese ＆ Western Medicine, Shanghai University of Traditional Chinese Medicine. MATERIALS ： Totally 60 healthy male Wistar rats of clean grade, aged 4 month, with body mass of 200 to 220 g, were enrolled in this study. Streptozotocin （STZ, Sigma Company of USA, Batch No. S-0130）. METHODS： This study was carried out in the Animal Experimental Center and Central Laboratory, Yueyang Hospital of Traditional Chinese ＆ Western Medicine during February 2005 to March 2006. （1） Fifteen rats were randomly chosen,serving as normal group.AU the other rats were intraperitoneally injected once with STZ to develop experimental diabetic rat models. If fasting blood glucose was ≥ 15 mmol/L,sensory nerve and motor nerve conduction velocity of sciatic nerve was obviously slowed, tail-swaying temperature threshold was increased and myelinated nerve fiber of sciatic nerve changed, DPN models were successful. The successful model rats were randomly assigned into 3 groups： model group, control group（electroacupuncture at non-meridian-non-acupoint）and electroacupuncture group [electroacupuncture at Zusan/i and Shenshu points], with 15 rats each. The rats in the normal group and model group were untouched. In the electroacupuncture group （electroacupuncture at Zusanfi and Shenshu points）, Shenshu point （double） and Zusanfi point （double） were chosen referencing to The Atlas of the Rat＇s Acupoints. G6805- Ⅱ electric acupuncture apparatus was used, and current intensity was controlled at 20 min/time, once every other day, 12 times within 24 days. In the control group, the tip of rat-tail was stimulated, and the concrete procedures were the same as in the electroacupuncture at Zusanfi and Shenshu points. （2） Motor nerve conduction velocity and sensory nerve conduction velocity of rats were detected with neuroelectrophysiology detector in the end of the treatment, and the expressions of CGT protein and mRNA of sciatic nerve were detected with immunohistochemical method and fluorescent quantitative PCR technique. MAIN OUTCOME MEASURES： （1） Motor and sensory nerve conduction velocity. （2） The expression of CGT protein and its mRNA. RESULTS： All the 60 rats entered the stage of result analysis. （1） Comparison of motor and sensory nerve conduction velocity of rats after electroacupuncture： Motor nerve conduction velocity of rats in the model group[（31.37±3.69） m/s], control group [（32.74±5.42） m/s] and electroacupuncture group [（41.30 ±1.15） m/s] was significantly lower than that in the normal group [（41.30±1.15） m/s, P 〈 0.01]; The sensory nerve conduction velocity of rats in the model group[（18.17±9.54） m/s], control group [（21.39±5.61） m/s]and electroacupuncture group [（35.81 ±4.59） m/s] was significantly lower than that in the normal group [（46.38± 6.32） m/s,P 〈 0.01]; The motor and sensory nerve conduction velocity of electroacupuncture group was significantly higher than that in the model group [（38.04±2.01） m/s vs. （32.74±5.42） m/s,（35.81±4.59） m/s vs. （21.39±5.61） m/s,P 〈 0.01]. （2） Comparison of the expression of CGT protein of sciatic nerve of rats： The number of CGT positive cells of sciatic nerve in model group, control group or electroacupuncture group was significantly smaller than that in normal group [（9 770.33±1 461.73）, （10 588.13±1119.52）, （27 518.27± 9 078.29）, （37 769.67±4 021.81）/μm^2,P 〈 0.01]; The number of CGT positive cells of the sciatic nerve in the electroacupuncture group was significantly larger than that in the model group and control group （P 〈 0.01）. The number of CGT positive cells of sciatic nerve was close between control group and electroacupuncture group （P 〉 0.05）. （3） Comparison of CGT mRNA expression of sciatic nerve of rats： Ct value of CGT mRNA of sciatic nerve of rats in the model group,control group and electroacupuncture group was significantly higher than that in the normal group （13.75±2.60,14.81±2.80,11.67±1.75,9.30±0.98, P 〈 0.01 ）; Ct value of CGT mRNA of sciatic nerve of rats in the electroacupuncture group was significantly lower than that in the model group and control group （P 〈 0.01）, and that was close between electroacupuncture group and control group （P 〉 0.05）. CONCLUSION ： Electroacupuncture at Zusanfi and Shenshu points can increase motor and sensory nerve conduction velocity of rats with DPN. It might be associated with up-regulating the expression of CGT mRNA and its protein.