The protective effect of the active components of ERPC on diabetic peripheral neuropathy in rats

Euonymus alatus, Radix trichosanthis, Panax notoginseng and Coptis chinensis are popular plants used in traditional Chinese medicine to treat diabetes.

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.

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.

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.

cERPC ameliorates diabetic peripheral neuropathy by attenuating electrophysiological, circulatory and morphological alterations, which is mediated by the Oct6-Krox20 pathway.