The Effect of Low Energy Red Light Irradiation on Mouse Bone Marrow Mesenchymal Stem Cell Fate
Date Issued
2011
Date
2011
Author(s)
Lee, Yen-Hua
Abstract
Due to their differentiation potential and self-renewal ability, mesenchymal stem cells (MSCs) can be applied for the treatment of some congenital or degenerative diseases. The efficacy of grafted MSCs is limited in proliferation, migration and differentiation ability. In addition, it is rare, only one MSC in 3.4 × 104 bone marrow cells. It is essential to culture and expand MSCs in vitro before putting them to therapeutic use. However, these abilities will decrease during in vitro culture process. Low energy red light irradiation was proved to be able to stimulate cell growth, migration, and adhesion. In order to validate the effect of low energy red light irradiation on mouse bone marrow MSCs proliferation, migration, adipogenic and osteogenic differentiation. MSCs were exposed to aluminum gallium indium phosphide light emitting diode at wavelength of 650 nm with different energy density (0, 0.3, 0.9 or 1.5 J/cm2, respectively). Cell proliferation was evaluated by using 3-(4, 5-dimethylithiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Cell migration ability was tested by wound healing assay. Adipogenic and osteogenic differentiation were analyzed by Oil Red O staining and Alizarin red staining and quantified by soluble dye measurement. The results showed that the cell number was significantly increased at day 4 in all irradiated groups (p < 0.05). In the wound healing assay, 12 hours after irradiation at the energy density of 0, 0.3, 0.9 or 1.5 J/cm2, the percentage of migration area was 28.2 ± 5.9, 37.6 ± 5.3, 44 ± 3.2, 41.4 ± 3.0%, respectively. To further investigate the differentiation ability, MSCs were incubated with adipogenic induction medium after low energy red light irradiation for 9 days. The oil droplets accumulation in irradiated groups were no significant different than control groups. After 3 days of osteogenic induction, the osteopontin mRNA expression was 40 % higher than control. However, there was no significant discrepancy (p>0.05) in calcium accumulation.
To elucidate the cell senescence condition after low energy red light irradiation. We test the telomere length, telomerase activity, cell cycle inhibitor p16 and p21 gene expression. The results showed that there was no significant aging found in these cells after they had exposed to red light irradiation. To further confirm the above investigated results, we transplanted the low energy red light irradiated mouse bone marrow MSCs into osteoporosis model mouse to validate the effect in vivo. The treatment group that injecting MSCs could increase the bone volume and trabecular bone number. Surprisingly, the bone density in the group of injecting the irradiated MSCs could not be increased. The reason why the low energy red light irradiation result in significant decrease of the MSCs function needs further investigation to clarify. In summary, low energy red light irradiation can stimulate mouse bone marrow MSCs proliferation, and slightly increase their differentiation and migration abilities in vitro. Moreover, the low energy red light irradiation won’t accelerate cell senescence.
To elucidate the cell senescence condition after low energy red light irradiation. We test the telomere length, telomerase activity, cell cycle inhibitor p16 and p21 gene expression. The results showed that there was no significant aging found in these cells after they had exposed to red light irradiation. To further confirm the above investigated results, we transplanted the low energy red light irradiated mouse bone marrow MSCs into osteoporosis model mouse to validate the effect in vivo. The treatment group that injecting MSCs could increase the bone volume and trabecular bone number. Surprisingly, the bone density in the group of injecting the irradiated MSCs could not be increased. The reason why the low energy red light irradiation result in significant decrease of the MSCs function needs further investigation to clarify. In summary, low energy red light irradiation can stimulate mouse bone marrow MSCs proliferation, and slightly increase their differentiation and migration abilities in vitro. Moreover, the low energy red light irradiation won’t accelerate cell senescence.
Subjects
phototherapy
mouse bone marrow mesenchymal stem cells
cell senescence
osteoporosis
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-100-R98626018-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):e9941e42f116113834102f11528d9e39