New Research of Nerve Growth Factor on Fracture Healing / 中国医学科学院学报

Fracture healing has long been a major concern for orthopedists.Currently,about 10% of fracture patients still have poor fracture healing or bone nonunion.In recent years,research has found that nerve growth factor(NGF)can promote fracture healing.This article reviews the mechanism and research progress of NGF in promoting fracture healing.NGF can promote vascular regeneration and nerve growth at callus and plays an important role in the proliferation and migration of bone cells.New animal experiments and clinical trials have confirmed the role of NGF in promoting fracture healing and further revealed its possible mechanism of action.Further research on NGF can provide new ideas for promoting fracture healing,especially for treating nonunion.

Effect of Tamibarotene on the proliferation and Tyrosine kinase receptor A,N-myc expressions of neuroblastoma SH-SY5Y cells / 中华实用儿科临床杂志

Objective To study the effect of Tamibarotene on the SH-SY5Y cell proliferation inhibition ability and the mRNA and protein expressions of tyrosine kinase receptor a (TrkA) and N-myc (MYCN) in order to provide some experimental bases for the treatment of neuroblastoma.Methods The SH-SY5Y cells were treated with different concentrations of Am80 (0,10,20,40,80,160 μmol/L) for 48 h,then Cell Counting Kit-8 (CCK-8) was used to test the cell proliferation.Reverse transcription PCR(RT-PCR) and Western blot were used to test the mRNA and protein expressions of TrkA and MYCN at 48 hours.Results When the concentration was 10 μmol/L,Am80 had no significant inhibitory effect on SH-SY5Y cells [(3.51 ± 1.68)％,inhibition ratio ＜ 5 ％];but when the concentration was 20 μmol/L,it showed weak inhibition [(9.60 ± 1.97) ％,inhibition ratio ＜ 10％].The inhibition rate of SH-SY5Y cell proliferation[(57.43 ± 4.95)％] was significantly enhanced at Am80 with a concentration of 80 μmol/L.The concentrations of Am80 could effectively inhibit SH-SY5Y cell proliferation in a dose-dependent manner(P ＜0.05).The expression of TrkA increased with the increase of Am80 concentration.Am80 significantly decreased the expression of MYCN in SH-SY5Y cells(10 μmol/L:0.65 ±0.05 vs.20 μmol/L:0.36 ±0.06),and the difference was statistically significant(P ＜ 0.05).Conclusions It is suggested that Am80 can effectively inhibit SH-SY5Y cell proliferation in a concentration-dependent manner.The underlying mechanism involves increasing the expression of TrkA by down-regulation of MYCN.

Effects of nerve growth factor on the expression of 67-kDa laminin receptor in human bile duct carcinoma cells / 中华消化外科杂志

Objective To investigate the effects of nerve growth factor (NGF) on the expression of 67-kDa laminin receptor (67LR) in human bile duct carcinoma QBC939 cells, and study the possible mechanism of perineural invasion and metastasis of bile duct carcinoma. Methods ( 1 ) The expression of a high-affinity receptor for NGF, TrkA, was detected by immunofluorescence staining. ( 2 ) QBC393 cells were pretreated by β-NGF at different concentrations ( 1, 10, 100,200 μg/L), and then the mRNA and protein expressions of 67LR were examined by Real-Time PCR and Western blot assay. QBC939 cells were divided into control group and β-NGF (1, 10, 100,200 μg/L) groups. (3) The ideal concentration of β-NGF was selected according to the results of previous tests, and then the mRNA and protein expressions of 67LR were re-examined by adding specific TrkA inhibitor K252a at different concentrations ( 100,200,300 nmol/L). QBC939 cells were divided into control group, β-NGF 100 μg/L group and K252a ( 100,200,300 nmol/L) groups. All data were analyzed by one-way analysis of variance or LSD-test. Results (1) A strong expression of TrkA was detected in the membrane of QBC939 cells. (2) The mRNA and protein expressions of 67LR in QBC939 cells were 0.35 ± 0.06 and 0. 32 ± 0.05 in the control group, 0.38 ±0.14 and 0.50 ±0.09 in the β-NGF 1 μg/L group, 0.62 ±0.14 and 0. 69 ±0. 13 in β-NGF 10 μg/L group, 0.90 ± 0.08 and 0.93 ± 0.07 in the β-NGF 100 μg/L group, and 0. 70 ± 0. 10 and 0. 76 ±0.07 in the β-NGF 200 μg/L group, there were significant differences among the five groups (F = 22. 4, 14. 6,P ＜0.05). The mRNA and protein expressions of 67LR in the β-NGF 100 μg/L group were significantly higher than those in the control group ( t = 19. 0, 21.0, P ＜ 0. 05 ). (3) The mRNA and protein expressions of 67LR in the QBC939 cells were 0.35 ±0.10 and 0.41 ±0.10 in the control group, 0. 88 ±0. 14 and 0.84 ±0.10 in the β-NGF 100 μg/L group, 0.80±0.08 and 0.76 ±0.04 in the K252a 100 nmol/L group, 0.67 ±0.12 and 0.61 ± 0.09 in the K252a 200 nmol/L group, and 0. 43 ± 0.07 and 0. 50 ± 0. 12 in the K252a 300 nmol/L group, there were significant differences among the five groups ( F = 14. 1, 8. 9, P ＜ 0.05 ). There were no significant differences in the mRNA and protein expressions of 67LR between the K252a 300 nmol/L group and the control group (t =1.02, 0. 85, P＞0.05). Conclusion In bile duct carcinoma cells, NGF enhances the expression of 67LR by combining with TrkA, which might be the mechanism of NGF mediating perineural invasion of bile duct carcinoma.