Effect of Huangqi Guizhi Wuwutang on Diabetic Peripheral Neuropathy in MKR Mice via Regulating Endoplasmic Reticulum Stress / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the mechanism of Huangqi Guizhi Wuwutang （HQGZWWT） in the treatment of diabetic peripheral neuropathy （DPN） in MKR mice via regulating endoplasmic reticulum （ER） stress. MethodThirty-two 8-week-old MKR mice （half were male and half were female） were fed with a high-fat diet for four weeks， and then 1% streptozotocin （STZ） was injected intraperitoneally for five days. After the blood glucose was stabilized， the mice were housed in the cage covered with ice bags for another one hour stimulation per day for four weeks. Mice with fasting blood glucose （FBG） value ≥11.1 mmol·L-1 were randomly divided into model group ， Huangqi Guizhi Wuwutang in original dosage group （30 g·kg-1·d-1）， Huangqi Guizhi Wuwutang in formula dosage group （6.25 g·kg-1·d-1）， and positive drug group （mecobalamin tablets， 0.17 mg·kg-1·d-1）. Another eight MKR mice of the same age were set as blank group and eight FVB mice were normal group. After four weeks of intragastric administration in each group， the change in FBG was tested， and hematoxylin and eosin （HE） staining and transmission electron microscope were used for observing the morphology of sciatic nerve tissue. In addition， the expression of c-Jun N-terminal kinase （JNK）， phosphorylated c-Jun N-terminal kinase （p-JNK） and inositol requiring enzyme 1α （IRE1α） proteins was determined by immunohistochemical test and Western blot （WB）. ResultCompared with the conditions in the normal group and blank group， the time of paw withdrawal， paw licking and tail flick in the model group was shortened （P<0.01）， and the conduction velocity of sciatic nerve was decreased （P<0.01）. Compared with the conditions in the model group， the behavioral and functional indicators were improved by HQGZWWT （P<0.05，P<0.01）. The immunohistochemical test revealed the JNK expression was elevated in the model group compared with the conditions in the normal group and blank group （P<0.05）， while that was lowered by HQGZWWT compared with the condition in the model group （P<0.05）. However， there was no difference among the treatment groups. According to the WB， the expression of IRE1α and p-JNK in the model group was enhanced compared with the conditions in the normal group and blank group （P<0.05，P<0.01）， while that was decreased by HQGZWWT compared with the condition in the model group （P<0.05，P<0.01）. No difference was observed between the HQGZWWTO and HQGZWWTF groups. ConclusionHQGZWWT can improve the neurophysiological function and pathological damage of sciatic nerve， which may be related to its delaying the ER stress response of sciatic nerve.