The mechanisms and relevant signal pathway of panax notoginseng saponins (PNS) on the differentiation of bone marrow stromal cells (BMSCs) into neuron-like cells were not clear.OBJECTIVE:
To study the effects of extracellular signal-regulated kinase (ERK)1/2 signal transduction pathway on the proliferation and differentiation of rat BMSCs into neuron-like cells.DESIGN, TIME AND SETTING:
The cytological in vitro study was performed at the Laboratory of Molecular Biology of the Medical College of Shantou University from May to October 2008.MATERIALS:
A total of 9 male Sprague Dawley rats aged 4-6 weeks were supplied by Experimental Animal Center, Medical College of Shantou University. PNS was produced by Guangxi Wuzhou Group Co., Ltd. ERK inhibitor PD98059 was produced by Cell Signaling Tech.METHODS:
Rat BMSCs were isolated and purified in vitro by the whole bone marrow method. At the third passage, BMSCs were induced and assigned into 3 groups. BMSCs in the induction group were incubated with medium supplemented with 10 μg/L basic fibroblast growth factor for 24 hours preindcution, and then incubated with formal α-MEM medium, containing 10 μg/L basic fibroblast growth factor, 2% dimethyl sulfoxide, 200 μmol/L butyl hydroxy anisol. A half of inductor was changed once every 24 hours. BMSCs in the PNS group were treated with preinductor and formal inductor supplemented with 100 mg/L PNS. BMSCs in the PD98059 group were additionally treated with 10 μmol/L PD98059 based on the medium in the PNS group.MAIN OUTCOME MEASURES:
Morphology was observed. Cell proliferation was measured by MTT assay. Nestin expression was determined by immunohistochemistry.RESULTS:
Following 6 hours of induction, a few BMSCs were cone-shaped, with an increased number of long processes, similar to neurons. Cell processes became more over time, and connected each other. Compared with the induction and PD98059 groups, BMSCs in PNS group significantly proliferated at 6, 12 and 24 hours (P < 0.05), and increased with prolonged time (P < 0.05). No significant difference was detected between the induction and PD98059 groups (P > 0.05). Compared with the induction group, Nestin-positive rate was significantly increased in the PNS group at 24 hours (P < 0.05), but Nestin-positive rate was significantly decreased in the PD98059 group (P < 0.05).CONCLUSION:
PNS can promote proliferation and differentiation of BMSCs. ERK1/2 specific inhibitor PD98059 can resist PNS effects, which indicated that ERK1/2 is the key signal pathway of the promotion effects of PNS on proliferation and differentiation of BMSCs into neurons.