Influence of low energy laser irradiation on the clinical treatment potential of adipose tissue-derived stem cells

Objective To investigate the effects of low level gallium aluminum arsenide (GaAlAs) laser irradiation on proliferation, cytokine secretion and adipogenic differentiation of cultured human adipose tissue-derived stem cells (hADSCs), and to find a safe and effective method for improving clinical treatment effect of ADSC. Methods The cultured hADSCs from human adipose tissue were treated by using 650nm GaAlAs laser irradiation at a single of 2, 4 and 8J/cm2 respectively. Cell proliferation was quantified by MTT assay, cytokine secretion was determined by ELISA, and adipogenic differentiation was examined by oil red staining respectively. In addition, the expression profiles of putative hADSC surface markers were determined by real-time PCR. Results MTT assay showed that treatment with GaAlAs laser irradiation at 4J/cm2 and 8J/cm2 (especially 4J/cm2) markedly promoted ADSCs proliferation from day 4 to day 6 after irradiation, when compared with the unirradiated group (P<0.05). ELISA results showed that the concentrations of VEGF, PDGF and TGF-βin culture supernatant were 287.5±15.2pg/ml, 36.0±0.7ng/ ml, and 292.6±10.5pg/ml when hADSCs were exposed to 4J/cm2 GaAlAs laser, and they were significantly higher than those of unirradiated group (145.3±21.6pg/ml, 26.7±0.6ng/ml and 130.6±6.0pg/ml, respectively, P<0.05). Quantitative PCR showed that the mRNA expression levels of cell surface marker CD13, CD29, CD44 and CD90 in hADSCs exposed to 4J/cm2 GaAlAs laser were 1.19, 22.05, 4.38 and 7.22 fold of those in unirradiated group (P<0.05). And the oil red staining revealed that GaAlAs laser irradiation could markedly accelerate the adipogenic differentiation of hADSCs (P