The effects of insulin-like growth factor-1 gene therapy and cell transplantation on rat acute wound model

Abstract

Background: Wound healing is a complex process. Different types of skin cells, extracellular matrix and variety of growth factors are involved in wound healing. The use of recombinant growth factors in researches and production of skin substitutes are still a challenge.

Objectives: Much research has been done on the effects of gene therapy and cell therapy on wound healing. In this experimental study, the effect of insulin-like growth factor (IGF-1) gene transfer in fibroblast cells was assessed on acute dermal wound healing.

Materials and methods: Fibroblasts were cultured and transfected with IGF-1. Lipofectamine 2000 was used as a reagent of transfection. Transgene expression levels were measured by the enzyme linked immunosorbent assay (ELISA). To study in vivo, rats (weighing 170-200 g) were randomly divided into three groups (five/group) and full-thickness wounds were created on the dorsum region. Suspensions of transfected fibroblast cells were injected into the wound and were compared with wounds treated with native fibroblast cells and normal saline. For the microscopic examination, biopsy was performed on day seven.

Results: In vitro, the maximum expression of IGF1 (96.95 pg/mL) in transfected fibroblast cells was 24 hours after gene transfer. In vivo, it was clear that IGF-1 gene therapy caused an increase in the number of keratinocyte cells during the wound healing process (mean of group A vs. group B with P value = 0.01, mean of group A vs. group C with P value = 0.000). Granulation of tissue formation in the transfected fibroblast group was more organized when compared with the normal saline group and native fibroblast cells.

Conclusions: This study indicated that the optimization of gene transfer increases the expression of IGF-1. High concentrations of IGF-1, in combination with cell therapy, have a significant effect on wound healing.

Keywords: Cell Transplantation; Fibroblast; Gene Therapy; IGF-1; Wound Healing.

Figure 1.. Injection of Cells Around The Wound

Figure 2.. A) Growth of Fibroblasts in the Implanted Dermis After 72 Hours (× 100 Magnification); B) The Cultured Fibroblasts After 19 Days

Figure 3.. Quantitative Analysis of IGF-1 Protein by the Reverse Method at 24, 48 and 72 Hours After Transfection: A Comparison Between Transfected Fibroblasts and Native Fibroblasts

Figure 4.. Macroscopic Findings of Wound Healing After Seven Days in the Three Groups

A: Wounds treated with transfected fibroblast cells. B; Wounds treated with native fibroblast cells. C; Wounds treated with normal saline.

Figure 5.. The Wound Area With Healthy Skin at Day Seven

The black arrows indicate the extent of the formed new epithelium. The red arrows indicate the ulcer area. A: Histology of wounds treated with transfected allogeneic fibroblasts with the IGF-1 gene (without ulcer). B: Wounds treated with native fibroblasts. C: Wounds treated with normal saline. (H and E staining; 4 × 10 magnification).