Effects of Tangtong formula on the expression of PI3K, Akt and mTOR in sciatic nerve of diabetic peripheral neuropathy rats / 国际中医中药杂志

ABSTRACT

Objective:To observe the effect of Tangtong formula on the expression of autophagy pathway proteins PI3K, Akt and mTOR in sciatic nerve of DPN rats, and to explore its mechanism. Methods:There were 60 male SD rats, 15 of which were randomly selected as the normal group, and the other rats were used to establish DPN model with STZ + ischemia-reperfusion method. Then they were divided into model group, Tangtong formula low-dose group and Tangtong formula high-dose group, with 15 rats in each group with random number table method. 36.67 g/kg Tangtong formula was administered by gavage in the high-dose group and 18.33 g/kg Tangtong formula was administered by gavage in the low-dose group, once a day. After 8 weeks of continuous gavage, the conduction velocity of sciatic nerve was detected. The mRNA and protein expression levels of PI3K, Akt and mTOR were detected by PCR and Western blot. The structure of sciatic nerve fibers was observed by HE staining. Results:Compared with the model group, the motor nerve conduction velocity, sensory nerve conduction velocity, muscle compound action potential and sensory nerve action potential in the low-dose Tangtong formula group and high-dose Tangtong formula group were increased ( P<0.05). The expression of PI3K mRNA(6.05±0.18, 3.36±0.29 vs. 11.57±1.93), Akt mRNA(1.26±0.13, 0.64±0.04 vs. 1.86±0.06), mTOR mRNA(1.82±0.11, 0.92±0.06 vs. 2.68±0.18) of sciatic nerve in rats of the low-dose and high-dose group were increased ( P<0.05). The expression of PI3K(0.40±0.00, 0.19±0.02 vs. 0.61±0.03), Akt(0.64±0.02, 0.45±0.01 vs. 0.83±0.02), mTOR(0.17±0.01, 0.09±0.00 vs. 0.34±0.01)of sciatic nerve in rats of the low-dose and high-dose group were increased ( P<0.05). The model group's nerve fibers were loose and swollen, myelin sheath became thin, and the axis Atresia, the neuromorphology of the low-dose and high-dose group tended to be normal, and the morphology of myelin sheath and axon were better. Conclusions:Tangtong formula could improve the conduction velocity and potential amplitude of sciatic nerve in DPN rats, reduce nerve injury and demyelinating changes, improve axon morphology and protect nerve fiber structure. Its mechanism might be related to activating PI3K/Akt/mTOR signal pathway and inhibiting excessive autophagy.