Abstract
Human adipose derived stem cells (hADSCs), with their impressive
differentiation potential, may be used in autologous cell therapy or grafting to replace
damaged tissues. Low intensity laser irradiation (LILI) has been shown to influence the
behaviour of various cells, including stem cells. This study aimed to investigate
the effect of LILI on hADSCs 24, 48 or 72 h post-irradiation and their differentiation
potential into smooth muscle cells (SMCs). Methodology: hADSCs were exposed to a
636 nm diode laser at a fluence of 5 J/cm2. hADSCs were differentiated into SMCs
using retinoic acid (RA). Morphology was assessed by inverted light and differential
interference contrast (DIC) microscopy. Proliferation and viability of hADSCs was
assessed by optical density (OD), Trypan blue staining and adenosine triphosphate
(ATP) luminescence. Expression of stem cell markers, β1-integrin and Thy-1, and SMC
markers, smooth muscle alpha actin (SM-αa), desmin, smooth muscle myosin heavy
chain (SM-MHC) and smoothelin, was assessed by immunofluorescent staining and
real-time reverse transcriptase polymerase chain reaction (RT-PCR). Results:
Morphologically, hADSCs did not show any differences and there was an increase in
viability and proliferation post-irradiation. Immunofluorescent staining showed
expression of β1-integrin and Thy-1 72 h post-irradiation. RT-PCR results showed a
down regulation of Thy-1 48 h post-irradiation. Differentiated SMCs were confirmed by
morphology and expression of SMC markers. Conclusion: LILI at a wavelength of 636
nm and a fluence of 5 J/cm2 does not induce differentiation of isolated hADSCs over a 72 h period, and increases cellular viability and proliferation. hADSCs can be differentiated into SMCs within 14 days using RA.