Influence of acidic peptide on the levels of nerve growth factor and brain-derived neurotrophic factor secreted by rat astrocytes

Yuhui AN; Xin ZHAO; Hongxia MA; Hongli MAO; Xiaoyan XIE; Xianjuan KOU

ABSTRACT

BACKGROUND:

Nerve growth factor (NGF) and brain-derived neurotrophic factor(BDNF) are very important to the survival and proliferation of nerve cells. In the patients with Alzheimer disease (AD), the levels of NGF and BDNF are low.

OBJECTIVE:

To investigate whether acidic peptide can stimulate rat astrocytes to secrete NGF and BDNF.

DESIGN:

A randomized control animal experiment.MATERLALS The experiment was finished in the First Laboratory of Institute of Biopeptide, Zhengzhou University; Cellular Culture Center,School of Basic Medical Sciences of Zhe ngzhou University from September 2003 to May 2005. Fifteen neonatal SD rats within 2 days after birth were selected.

METHODS:

① The cerebral cortex of the neonatal SD rats was removed under sterile condition, the astrocytes were isolated and cultured, and then identified with the glial fibriliary acidic protein immunohistochemical staining. ② The cultured astrocytes were randomly divided into six groupblank control group, serum control group, positive control group and acidic peptide treated groups. No treatment was given in the blank control group,serum of 0.2 in volume fraction and 1 000 U/mL interferon were added in the serum control group and positive control.group, 37.5, 75 and 150 mg/L acidic peptides were added in the acidic peptide treated groups respectively. ③ The astrocytes of the 2nd generation, which covered the whole bottom of bottle, were digested to single cell suspension, and then inoculated to three 12-well plates equally at 5×105 /mL. The survival rate and the contents of NGF and BDNF in the supernatant of each group were determined at 24, 48 and 72 hours respectively.MAIN OUTCOME

MEASURES:

① Cell numbers and survival rates at different culture time-points; ② Effect of acidic peptide on the proliferation of astrocytes in rats; ③ Changes of NGF and BDNF in the supernatant of astrocytes at different culture time-points.

RESULTS:

① As compared with the blank control group, the cell numbers and survival rates at 24, 48 and 72 hours were obviously increased in the acidic peptide groups treated with 75 and 150 mg/L (P＜0.05, 0.01,0.001), but not obviously increased in the acidic peptide group treated with 37.5 mg/L. ② As compared with the blank control group, the rates of proliferation in the acidic peptide groups treated with 37.5, 75 and 150 mg/L were all significantly increased (17.5%, 45.5%, 72.5%, P＜0.001). ③ As compared with the blank control group, the absorbance (A) values of NGF in the supernatant at 24, 48 and 72 hours were all markedly increased in the acidic peptide groups treated with 37.5, 75 and 150 mg/L (P＜0.001),and the A values of BDGF in the supernatant at 48 and 72 hours were significantly increased (P＜0.05, 0.01).

CONCLUSION:

Acidic peptide can increase the secretions of NGF and BDNF of rat astrocytes to different extent.