Combination Fractional Carbon Dioxide Laser Treatment and Bone Marrow Mesenchymal Stem Cell Therapy Enhances the Treatment of Skin Photoaging in a Murine Model System

Abstract

Background: Fractional carbon dioxide lasers and bone marrow mesenchymal stem cells (BMSCs) are commonly employed in the treatment of skin photoaging.

Objective: This study was developed to explore the effects of combination carbon dioxide laser treatment and BMSC injection on skin photoaging and the underlying molecular mechanisms.

Methods & materials: In total, 24 mice with experimentally photoaged skin were separated into control, carbon dioxide fractional laser treatment, combination therapy, and BMSC injection groups. Samples of dorsal skin from these animals were subjected to hematoxylin and eosin staining or Masson's trichrome staining. In addition, immunohistochemical analyses and real-time polymerase chain reaction analyses were conducted to detect MMP-3 and MMP-9 expression.

Results: After 1 week, both dermal thickness and collagen fiber density were significantly increased in the BMSC and combination treatment groups as compared to the control group (P<0.05), while both of these parameters were significantly increased in all treatment groups after 4 weeks relative to the control group (P<0.05), with the most pronounced effect in the combination therapy group (P<0.05). MMP-3 and MMP-9 mRNA and protein levels in the treatment groups were decreased relative to the control group after 4 weeks.

Conclusion: Combination BMSC and carbon dioxide laser therapy was more effective than either of these therapeutic approaches in isolation as a treatment for photoaged skin. The improvement of effect may be due to the decrease of MMP-3 and MMP-9 expression in combination therapy.

Keywords: bone marrow mesenchymal stem cell; fractional carbon dioxide laser; matrix metalloproteinase; mouse model; photoaging.

Figure 1

Flow cytometry analysis of bone marrow mesenchymal stem cells. BMSC surface antigen profiles were assessed via flow cytometry, revealing these cells to express the mesenchymal stem cell markers CD44, CD90, and CD105.

Figure 2

Murine skin photoaging model establishment. (A) Images of the skin surface for mice in the control (left) and UV-irradiated (right) groups after 8 weeks. (B) Hematoxylin and eosin staining of murine skin samples was conducted after 8 weeks (left: control; right: UV-irradiated group; 100×). (C) Masson’s trichrome staining of murine skin samples was conducted after 8 weeks (left: control; right: UV-irradiated group; 100×).

Figure 3

Clinical and histopathological analyses of photoaged murine following the application of different therapeutic regimens. (A) Images of the skin surface from mice in the control, laser, BMSC, and combination treatment groups following a 1- or 4-week post-treatment period. (B) Skin samples from the indicated groups were collected at 1 or 4 weeks post-treatment and subjected to hematoxylin and eosin staining (100×). (C) Skin samples from the indicated groups were collected at 1 or 4 weeks post-treatment and subjected to Masson’s trichrome staining (400×).

Figure 4

Assessment of clinical scores and skin thickness at 1 or 4 weeks post-treatment. (A) Clinical score of roughness, elasticity, and wrinkles. (B) Dermal thickness quantified from H&E staining. *P<0.05.

Figure 5

Assessment of collagen fibers and MMP-3/MMP-9 expression at 1 or 4 weeks post-treatment. (A) Collagen fiber density percentages. (B) Collagen fiber optical density. The mRNA levels of MMP-3 (C) and MMP-9 (D) were assessed at 1 week and 4 weeks post-treatment. *P<0.05, **P<0.01.

Figure 6

MMP-3 and MMP-9 in photoaged mouse skin. (A) MMP-3 expression at 1 week or 4 weeks post-treatment as measured via immunohistochemical staining (400×). Skin samples were collected from mice in the control, laser, BMSC, and combination treatment groups. (B) MMP-9 expression at 1 week or 4 weeks post-treatment as measured via immunohistochemical staining (400×).