Chinese Medicine in Diabetic Peripheral Neuropathy: Experimental Research on Nerve Repair and Regeneration

Table 2

Key data from cited studies in Chinese literature.

First author (year) ref.	Tissue/cells	Experimental treatment	Control treatment	Methods for main indicators	Main outcomes	Author's conclusion
Sun (2009) [2]	Schwann cells	Serum containing Jinmaitong (Sinew-Channel Unobstruction)	Neurotropin	MTT assay for proliferation of Schwann cells	Promoted proliferation of Schwann cells and increased expression of NGF of Schwann cells cultured in high glucose	“Can promote the proliferation of Schwann cells and increase the expression of NGF of Schwann cells cultured in high glucose”
Wu (2009) [3]	Schwann cells	Allyl glycoside extracted from Herba Rhodiolae	Shenmaizhusheye (Ginseng-Ophiopogonis injection)	XTT method and 3H-TdR incorporative method for activity and proliferative capability of Schwann cells, respectively	Improved proliferative capability of Schwann cells	“Can improve inhibitory effect on proliferative capability of Schwann cell in high glucose milieu, in vitro”
Ji (2009) [4]	Sciatic nerve	Jiangtangshuluofang (Decrease Glucose Free Collaterals Prescription) for 8 W	Methycobal and Gliclazide	Radioimmunoassay for insulin level and HbA1c; tunel for apoptosis; immunohistochemical method for expression of Bcl-2, Bax, and caspase-3	Increased Bcl-2 expression; reduced caspase-3 and Bax expression; decreased apoptosis of Schwann cells.	“Can increase the insulin level and lower HbA1c level in diabetic rats, inhibit Schwann cells apoptosis; the mechanism might be related to its inhibition of caspase-3 and Bax expression, and promoting the expression of Bcl-2”
Liu (2010) [5]	Schwann cells	Huangqi (Radix Astragali), Danshen (Radix Salviae miltiorrhizae), Shanyao (Rhizoma Dioscoreae), and compounds of three herbal medicines	None	Flowcytometer for apoptosis rate of Schwann cells; real-time PCR for expression of Bcl-2 and caspase-3 mRNA; Western blotting for expression of Bcl-2 and caspase-3 protein	Decreased apoptosis rate; increased Bcl-2 mRNA and protein expression; decreased caspase-3 mRNA expression in astragalus, salvia and compound groups; decreased expression of caspase-3 protein in astragalus, yam, and compound groups.	“The apoptosis of Schwann cell co-cultured with endothelial cell in high glucose can be protected by Chinese herbs, different herbs have different effect, the compound intervention group was the best”
Zhao (2011) [6]	Schwann cells	Serum containing Jinmaitong (Sinew-Channel Unobstruction)	Vitamin C	Immunofluorescence method for the expression of iNOS; real-time fluorescence quantitative PCR for p22-phox mRNA expression	Deceased expression of iNOS and p22-phox mRNA of Schwann cells	“Can down-regulate the expression of iNOS protein of NADPH oxidative p22-phox subunit mRNA of Schwann cells cultured in higher glucose medium”
Piao (2011) [7]	Schwann cells	Serum containing Jinmaitong (Sinew-Channel Unobstruction)	Vitamin C	Enzyme-linked immunoabsorbant assay for 8-OHdG level; immunofluorescence for expression of caspase-3 protein; real-time fluorescence quantitative PCR for expression of caspase-3 mRNA	Decreased 8-OHdG level; decreased expression of caspase-3 protein and mRNA in the supernatant of Schwann cells	“Can improve high-glucose induced oxidative injury of DNA apoptosis in Schwann cells, suggesting it might improve oxidative injury and apoptosis in diabetic neuropathy”
Qu (2008) [8]	Sciatic nerve	Jinmaitong (Sinew-Channel Unobstruction) for 16 W	Neurotropin	Real-time fluorescence quantitative PCR for NGF mRNA of sciatic nerve; immunohistochemical method for NGF protein of sciatic nerve	Increased NGF and NGF mRNA in sciatic nerve.	“Can upregulate the expression of NGF protein and NGF mRNA in sciatic nerve of rats with DPN”
Deng (2007) [9]	Sciatic nerve	Qitengtongluoyin (Astragalus Vine Free Collaterals Decoction) for 6 W	None	Immunohistochemical assay for expression of NGF and substance P in sciatic nerve	Improved changes of sciatic nerve, increased expression of NGF and substance P in sciatic nerve	“Has the preventive and treatment effects on pathological changes of sciatic nerve of DPN rats. It's possible mechanism may be associated with the promotion of expression of endogenous NGF and substance P”
Yu (2004) [10]	Sciatic nerve	Tangmoning (Glucose End Peace Granules) for 6 W	Methycobal	Reverse transcription PCR for NGF mRNA of sciatic nerve	Increased expression of NGF mRNA	“Appears to upregulate the expression of NGF mRNA of sciatic nerve in diabetic rats”
Xu (2009) [11]	Sciatic nerve, serum	Yiqitongluofazufang (Tonify Qi Free Collaterals Prescription) for 6 W	Methycobal	ELISA for serum NGF	Increased NO, decreased MDA, and increased NGF; improved histopathological changes	“Can prevent DPN via improvement of MDA, NO, and NGF”
Wang (2010) [12]	Sciatic nerve	Tangbikang (Sugar Blockage Recovery) for 8 W	Methycobal	Real-time fluorescence quantitative PCR for NGF mRNA of sciatic nerve; ELISA for NGF level in serum	Increased NGF level in serum and increased NGF mRNA expression.	“Can increase the NGF protein and mRNA expression to play an important role of peripheral nerve protection”
Ma (2007) [13]	Sciatic nerve	Morus alba extract for 8 W	Methycobal	Pathological observation for expression of NGF and myelin basic protein	Increased expression of NGF and myelin basic protein in sciatic nerve	“Morus alba extract has functions of increasing the expression of NGF and myelin basic protein thus improving the DPN”
Dong (2007) [14]	Sciatic nerve	Shenshu (BL 23), Zusanli (ST 36); G6805-II electroacupuncture device, continuous wave, frequency 2 Hz, 20 min every other day, for 12 times	Methycobal	Immunity and fluorescent quantitation PCR for NGF mRNA, and immunohistochemical staining analysis for NGF protein-positive cells of sciatic nerve	Increased expression of NGF protein and NGF mRNA in sciatic nerve.	“Can upregulate the expression of NGF protein and NGF mRNA, and promote sciatic nerve repair in DPN rats”
Huang (2010) [15]	Sciatic nerve	Positive electrode located 1.0 cm above the interior of proximal greater trochanter, distal fibular head and the inside of each 0.3 cm. Needle 0.5 cm in depth, with the stimulus intensity of 2-3 V, at the frequency of 100 beats/min, 45 min each day	None	Reverse transcriptase-PCR for expression of NGF mRNA and IGF-1 mRNA of sciatic nerve	From 2nd week, the expression of NGF mRNA and IGF-1 mRNA increased, at 10th week; the expression of NGF mRNA and IGF-1 mRNA sustained in higher level.	“Can elevate the mRNA expression of NGF and IGF-1 in sciatic nerve of diabetic rat, which may be one of the mechanisms of acupuncture on diabetic neuropathy”
Yin (2008) [16]	Sciatic nerve	Moxaed at the points of Yishu (Ex-B3) and Zusanli (ST 36), 15 min each point, once daily for 56 consecutive days	None	Neuroelectrophysiological detection for SNCV; ELISA for NGF of sciatic nerve	Decreased blood glucose level; increased SNCV; increased NGF content in sciatic nerve.	“The improving effect of moxibustion on diabetic peripheral neurological symptoms in a rat model of DPN may be related to an increase in the NGF content and promotion of peripheral neuroprotection”
Wang (2010) [17]	Sciatic nerve	Jinmaitong (Sinew-Channel Unobstruction) for 8 W	Neurotropin	The hydrothermal tail-flick and pain threshold to mechanical stimulation; SABC immunohistochemistry method for CNTF expression and real-time fluorescence quantitative PCR for CNTF mRNA expression in sciatic nerve	The pain thresholds were raised and tail-flick latencies were shortened; the expression of CNTF mRNA and protein was increased	“Can obviously upregulate the expression of CNTF mRNA and protein in the sciatic nerve of rats with neuropathy”
Wang (2010) [18]	Schwann cells	Serum containing Jinmaitong (Sinew-Channel Unobstruction)	Neurotropin	SABC immunohistochemistry method for CNTF expression and real-time fluorescence quantitative PCR for CNTF mRNA expression in Schwann cells	Increased CNTF and CNTF mRNA expression in Schwann cells	“Can upregulate the expression of CNTF and CNTF mRNA of rat Schwann cells in cultured high glucose medium, so as to improve DPN”
Zeng (2005) [19]	Sciatic nerve	Xiaokelingnongsuoye (Diabetes Agility Concentration Fluid) for 8 W	Methycobal	Relative quantity PCR for IGF mRNA	Increased expression of IGF-1 mRNA in sciatic nerve	“Is involved in the regulation of IGF-1 mRNA expression, and probably prevents diabetic peripheral neuropathy from deterioration”
Xu (2009) [20]	Sciatic nerve	Qingyingtang (Clearing Nutritive Qi Decoction) for 10 W	Methycobal	ELISA for IGF-1 in serum; IGF-1 in sciatic nerve and liver	Increased IGF-1 level in serum, liver and sciatic nerve	“Increase the expression of IGF-1 in tissue, and have effects of nerve repair in DNP rats”
Wang (2010) [21]	Sciatic nerve	Tangmoning (Glucose End Peace Granules) for 8 W	None	Western blotting for expression of NGF and IGF-1 in sciatic nerve; sciatic ultrastructure observation by transmission electron microscope	Increased expression of NGF and IGF-1; pathological changes of sciatic nerve were improved by transmission electron microscope	“Has some protective effect on sciatic nerve in diabetic rats. The mechanism may be related to the upregulation of the expression of NGF and IGF-1 proteins.”
Zhang (2008) [22]	Serum	Xiaoketongbikeli (Diabetes Free Obstruction Granula)	Methycobal	Radioimmunoassay for IL-1β and TNF-α, ELISA for CD54	Reduced the level of IL-1β, TNF-α, and CD54	“Can relieve or improve diabetic peripheral nerve injury by interfering with inflammation factors in diabetes”

MTT: methyl thiazolyl tetrazolium; ELISA: enzyme-linked immunoabsorbent assay; MDA: malondialdehyde; DPN: diabetic peripheral neuropathy; STZ: streptozotocin; NGF: nerve growth factor; ALL: Alloxan; PCR: polymerase chain reaction; CNTF: ciliary neurotrophic factor; SNCV: sensory nerve conduction velocity.