Low-level laser irradiation promotes proliferation of cryopreserved adipose-derived stem cells

ABSTRACT Objective To evaluate the effect of low-level laser irradiation on proliferation and viability of murine adipose-derived stem cells previously submitted to cryopreservation. Methods Adipose-derived stem cells were isolated from inguinal fat pads of three mice, submitted to cryopreservation in fetal bovine serum with 10% dimethylsulfoxide for 30 days and then thawed and maintained in normal culture conditions. Culture cells were either irradiated or not (control) with an InGaAIP diode laser at zero and 48 hours, using two different energy densities (0.5 and 1.0J/cm2). Cell proliferation was evaluated by trypan blue exclusion method and MTT assay at intervals of zero, 24, 48, and 72 hours after the first laser application. Cell viability and apoptosis of previously cryopreserved cells submitted to laser therapy were evaluated by flow cytometry. Results The Irradiated Groups (0.5 and 1.0J/cm2) showed an increased cell proliferation (p<0.05) when compared to the Control Group, however no significant difference between the two energy densities was observed. Flow cytometry revealed a percentage of viable cells higher than 99% in all groups. Conclusion Low-level laser irradiation has stimulatory effects on the proliferation of adipose-derived stem cells previously submitted to cryopreservation.

摘要 目的：本研究旨在评估低强度激光照射对经冷冻保存的小鼠脂肪来源干细胞（murine adipose-derived stem cells）的增殖与存活能力的影响。方法：从3只小鼠的腹股沟脂肪垫中分离脂肪来源干细胞，将其置于含10%二甲基亚砜（dimethylsulfoxide）的胎牛血清（fetal bovine serum）中进行30天的冷冻保存，随后复苏并置于常规培养条件下培养。将培养细胞分为照射组与对照组，分别在首次激光照射后的0小时与48小时，采用铟镓铝磷（InGaAIP）二极管激光器对照射组实施照射，照射采用两种能量密度：0.5 J/cm²与1.0 J/cm²，对照组不接受照射。分别于首次激光照射后的0、24、48、72小时，采用台盼蓝排斥法（trypan blue exclusion method）与MTT比色法（MTT assay）检测细胞增殖情况。通过流式细胞术（flow cytometry）检测经激光干预的冷冻复苏细胞的细胞活力与细胞凋亡（apoptosis）水平。结果：与对照组相比，两个激光照射组（0.5 J/cm²与1.0 J/cm²）的细胞增殖水平均显著升高（p<0.05），但两组能量密度之间未检测到显著差异。流式细胞术检测结果显示，所有组别活细胞百分比均高于99%。结论：低强度激光照射可促进经冷冻保存的小鼠脂肪来源干细胞的增殖。