Cationic star-shaped polymer as an siRNA carrier for reducing MMP-9 expression in skin fibroblast cells and promoting wound healing in diabetic rats

作者：Li Na; Luo Heng Cong; Yang Chuan; Deng Jun Jie; Ren Meng; Xie Xiao Ying; Lin Diao Zhu; Yan Li^*; Zhang Li Ming

来源：INTERNATIONAL JOURNAL OF NANOMEDICINE, 2014, 9: 3377-3387.

DOI：10.2147/IJN.S66368

• gene carrier
• small interfering RNAs
• matrix metalloproteinase-9
• diabetic foot ulceration

Background: Excessive expression of matrix metalloproteinase-9 (MMP-9) is deleterious to the cutaneous wound-healing process in the context of diabetes. The aim of the present study was to explore whether a cationic star-shaped polymer consisting of beta-cyclodextrin (beta-CD) core and poly(amidoamine) dendron arms (beta-CD-[D-3](7)) could be used as the gene carrier of small interfering RNA (siRNA) to reduce MMP-9 expression for enhanced diabetic wound healing.
Methods: The cytotoxicity of beta-CD-(D-3)(7) was investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assay (MMT) method in the rat CRL1213 skin fibroblast cell line. The transfection efficiency of beta-CD-(D-3)(7)/MMP-9-small interfering RNA (siRNA) complexes was determined by confocal microscopy and flow cytometry. Quantitative real time (RT) polymerase chain reaction was performed to measure the gene expression of MMP-9 after the transfection by beta-CD-(D-3)(7)/MMP-9-siRNA complexes. The beta-CD-(D-3)(7)/MMP-9-siRNA complexes were injected on the wounds of streptozocin-induced diabetic rats. Wound closure was measured on days 4 and 7 post-wounding.
Results: beta-CD-(D-3)(7) exhibited low cytotoxicity in fibroblast cells, and easily formed the complexes with MMP-9-siRNA. The beta-CD-(D-3)(7)/MMP-9-siRNA complexes were readily taken up by fibroblast cells, resulting in the downregulation of MMP-9 gene expression (P<0.01). Animal experiments revealed that the treatment by beta-CD-(D-3)(7)/MMP-9-siRNA complexes enhanced wound closure in diabetic rats on day 7 post-wounding (P<0.05).
Conclusion: beta-CD-(D-3)(7) may be used as an efficient carrier for the delivery of MMP-9-siRNA to reduce MMP-9 expression in skin fibroblast cells and promote wound healing in diabetic rats.