Effect of Low Power Laser Irradiation on the Proliferation and Differentiation of PC12 Nerve Cells

ABSTRACT

OBJECTIVE: We examined the effect of low power laser irradiation (LPLI) on the proliferation and differentiation of PC12 nerve cells. METHOD: After seeding 4x10(5) PC12 nerve cells each in the 24 well-culture dishes, we cultured them for 6 days with RPMI1640 media. LPLI (650 nm, 5 mW, 5 sec) was applied for 1 day, 2 days and 3 days (1, 2 and 3-day-LPLI groups) consecutively. For the degree of proliferation of PC12 nerve cells, we compared the total cell number at 6th day after LPLI by MTT cell proliferation assay. For the degree of differentiation, we compared the length of neurite out-growth and the expression of RT97 at 6th day after adding nerve growth factor on each group. RESULTS: The total cell numbers were increased significantly after LPLI, but those increments were not significant among 1, 2, and 3-day-LPLI groups. The numbers of the differentiated PC12 nerve cells and the expressions of RT97 were diminished serially according to the number of days of LPLI. CONCLUSION: We conclude that LPLI increased the proliferation and decreased the differentiation of PC12 nerve cells. We could suggest that single or short-term use of LPLI on the injured nerve should be helpful for enhancing the neural regeneration in vivo.