LPLI enhances the proliferation of D1 cells.

<p>Cells were treated with LPLI at doses of 0 (control), 1, 2, or 4 J/cm² and assayed at days 1, 3 and 5. (<b>A</b>) LDH leakage was analyzed to evaluate cell cytotoxicity. There were no significant differences between the groups (n = 12). (<b>B</b>) Cell numbers were counted at indicated times. There were no differences between the cell numbers of each group at day 1 and day 3. At day 5, the cell numbers of the LPLI groups treated with 2 and 4 J/cm² were significantly higher than that of control group (n = 6). (<b>C</b>) An MTT assay was performed, and the optical densities were measured. Similar results with the cell counting analysis was found (n = 18). The statistical significance levels were as follows: * p<0.05, ** p<0.01, and *** p<0.001 compared with the control group.