Effect of bushen yizhi formula on neurotransmitter release in rat models with Alzheimer disease

Zhenguo ZHONG; Maocai LIU; Shilong LAI; Jie GAO; Shuyi CHENG

ABSTRACT

BACKGROUND:

The decrease of activity level of choline acetyltransferase (ChAT) and reduction of membrane protein of synaptic vesicles are the main biochemical indexes in Alzheimer disease. Traditional Chinese bushen yizhi formula is of the effects of strengthening the kidney, replenishing qi, generating marrow and nourishing the brain, its medicine-containing serum can effectively protect these changes resulting from amyloid protein.

OBJECTIVE:

To investigate whether the medicine-containing serum of bushen yizhi formula can improve the pathological injury of neurons induced by amyloid protein metabolites in Alzheimer disease, thus to estimate the therapeutic effect of bushen yizhi formula on Alzheimer disease.

DESIGN:

A randomized and controlled trial.

SETTING:

Institute of Neuroscience, Second Affiliated Hospital, Guangxi College of Traditional Chinese Medicine, Nanning 530011, Guangxi Zhuang Nationality Autonomous Region, China; Encephalopathic Institute of Guangzhou University of Traditional Chinese Medicine.MATERIALSThe experiment was conducted from September 2003 to March 2004 at the Research and Development Center of New Drugs of Guangxi College of TCM. Totally 60 healthy Wistar rats of clean grade,three months, were at random divided as blank control and bushen yizhi groups, with 30 in each group. The bushen yizhi formula consisted of Fructus Lycii, Fructus Cnidii, Radix Gingeng, Radix Polygoni Multiflori,Cortex Moutan Radicis, Borneolum, etc. The medicine was prepared before use as 0.176 g/Ml liquid(including 1.13 g/Ml rude drugs).

METHODS:

① Each of the rats in bushen yizhi group was by garage given 1.0-1.5 Ml prepared liquid per day for consecutive 30 days. Within 4hours after the last administration the serum was isolated at 5 000 r/min for 5 minutes, filtered aseptically, the compliment was inactivated at 56 ℃,then the medicine-containing serum was obtained. The rats in blank control group were given saline of the same volume, and the serum was prepared with the same method. ② For NG108-15 cells, the concentration of amyloid protein 25-35 segments in the culture liquid was 5 μ mol/L, or 1-42 segments, 200 nmol/L, was suitable. ③ NG108-15 cells was first in cubated for a day in CO2 incubator with Dulbecco-improved Eagle medium of 0.1 molarity at 37 ℃, then 5 μmol/L amyloid protein 25-35 segment or 200 nmol/L segment 1-42 was added to continuously incubate for a day, after that the cell models of Alzheimer disease was ready. Then 50 g/L medicine-containing serum or Dulbecco-improved Eagle medium of blank control group serum was taken to replace the original culture liquid, and the amyloid protein segments of the above-mentioned concentration was still added for maintaining the cell models of Alzheimer disease, after 5 days'differentiation incubation, the indexes were detected with those in non-amyloid protein as control. ④ Western blotting, radioimmunoassay and electrophysiological examination were used to investigate the ChAT activity,synapsin protein level and rate of functional synapse formation of NG108-15cells in Alzheimer disease after treatment with the medicine-containing serum of bushen yizhi formula.MAIN OUTCOME

MEASURES:

The effects of the medicine-containing serum of bushen yizhi formula on ChAT activity, synapsin protein level,rate of functional synapse formation of NG108-15 cells and frequency of miniature plate potential in NG108-15 cells.

RESULTS:

Totally 60 rats involved all entered the final result analysis.① The effect of the medicine-containing serum of bushen yizhi formula on ChAT activity In the conditions when there was no amyloid protein or the final concentration of amyloid protein 1- 42 was 200 nmol/L, the ChAT activity in bushen yizhi group was obviously higher than that in blank control group [(1651.2±134.5), (1336.1±268.2), ( 586.1±223.4),(1290.7±381.5)μmol/(g·h); P ＜ 0.05] . ② The effect of the medicinecontaining serum of bushen yizhi formula on synapsin protein level The absorbance values of synapsin Ⅰa and Ⅰb, in the conditions when there was no amyloid protein, amyloid protein 25-35 and 1-42, were respectively 5.02, 1.36 and 2.46 in bushen yizhi group; and 3.18, 0.57 and 0.71 in blank control group. The values in bushen yizhi group were respectively 1.6,2.4 and 3.5times those in blank control group. ③ The effect of the medicine-containing serum of bushen yizhi formula on functional synapse formation of NG108-15 cells In the conditions when there was no amyloid protein or amyloid protein 1-42, the levels of functional synapse formation in bushen yizhi group wereall higher than those in blank control group [(90.6±6.0)%, (63.2±17.0)%, (58.0±13.1)%, (34.2±13.0)% ;P＜0.05].④ The effect of the medicine-containing serum of bushen yizhi formula on frequency of miniature plate potential in NG108-15 cells In the conditions when there was no amyloid protein or amyloid protein 1-42, the frequencies of miniature plate potential in bushen yizhi group were all higher than those in blank control group [(9.28±4.1), (5.48 ±5.14), (5.55±5.85),(3.05±4.46)/min; P ＜ 0.01, P＜ 0.05].

CONCLUSION:

In the conditions when there existed no amyloid protein or amyloid protein, the medicine-containing serum of bushen yizhi formula can raise ChAT activity, not only correct the decrease of cellular synapsin caused by amyloid protein, but also raise the expression of synapsin protein, the rate of functional synapse formation and neurotransmitter release under the condition of no amyloid protein. It was shown that the prescription can antagonize the pathological development of Alzheimer disease, and play the therapeutic effect through enhancing the release power of neurotransmitter.