The protective effect of the active components of ERPC on diabetic peripheral neuropathy in rats.
BACKGROUND
Euonymus alatus, Radix trichosanthis, Panax notoginseng and Coptis chinensis are popular plants used in traditional Chinese medicine to treat diabetes.


OBJECTIVE
The aim of the study is to investigate the therapeutic effect of the active components of Euonymus alatus, Radix trichosanthis, Panax notoginseng and Coptis chinensis (cERPC) on diabetic peripheral neuropathy in the rats and explore the underlying mechanism involved.


METHODS
After diabetes was induced in rats for 20 weeks, cERPC or water was administered for 12 weeks. After a hot plate test, motor nerve conduction velocity and sciatic nerve blood flow were determined; the sciatic nerves were isolated for toluidine blue staining; and the fibre area, fibre diameter, axon area, axon diameter and myelin thickness were evaluated. The levels of the myelin basic protein, myelin protein zero, Oct6 and Krox20 were measured by western blot or immunofluorescence.


RESULTS
cERPC was efficient in reducing the response latency, increasing motor nerve conduction velocity, enhancing sciatic nerve blood flow and ameliorating the pathological changes in diabetic rats. cERPC also had a role in increasing the levels of myelin basic protein and myelin protein zero and improving the expression of Oct6 and Krox20 in sciatic nerves of diabetic rats.


CONCLUSIONS
cERPC ameliorates diabetic peripheral neuropathy by attenuating electrophysiological, circulatory and morphological alterations, which is mediated by the Oct6-Krox20 pathway.
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China; Institute of Basic Theory for Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China. Electronic address: haogaimei@bucm.edu.cn.
Gai-Mei
GM
Hao
College of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China. Electronic address: liuyg0228@163.com.
Yong-Gang
YG
Liu
Institute of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China. Electronic address: nayattmm@vip.sina.com.
Yan
Y
Wu
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China. Electronic address: 427781395@qq.com.
Wei
W
Xing
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China. Electronic address: ss3008@126.com.
Shu-Zhen
SZ
Guo
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China. Electronic address: doctor_wangyong@sina.com.
Yong
Y
Wang
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China. Electronic address: 1065092305@qq.com.
Zheng-Lin
ZL
Wang
Modern Research Center for Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China. Electronic address: 185956425@qq.com.
Chun
C
Li
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China. Electronic address: lvtiantian471398@163.com.
Tian-Tian
TT
Lv
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China. Electronic address: 2357565806@qq.com.
Hong-Liang
HL
Wang
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China. Electronic address: shitianjiao@bucm.edu.cn.
Tian-Jiao
TJ
Shi
College of Basic Medicine, Key Laboratory of Ministry of Education (Syndromes and Formulas), Key Laboratory of Beijing (Syndromes and Formulas), Beijing University of Chinese Medicine, Beijing, China. Electronic address: wangwei26960@126.com.
Wei
W
Wang
Institute of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China. Electronic address: hanjing8585@163.com.
Jing
J
Han
D000818:Animals; D001369:Axons / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy; D003929:Diabetic Neuropathies / Q000473:pathology / Q000517:prevention & control*; D004365:Drugs, Chinese Herbal / Q000627:therapeutic use*; D008297:Male; D009046:Motor Neurons / Q000187:drug effects; D009185:Myelin Proteins / Q000378:metabolism; D009186:Myelin Sheath / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D009431:Neural Conduction / Q000187:drug effects; D010147:Pain Measurement / Q000187:drug effects; D020011:Protective Agents / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D012584:Sciatic Nerve / Q000098:blood supply
D004365:Drugs, Chinese Herbal; D009185:Myelin Proteins; D020011:Protective Agents
Diabetes; Neurodegenerative disorders; Pharmacodynamics; Signal transduction; Traditional Chinese medicine