ÜÇ BOYUTLU YAZICI ARACILIĞI İLE HAZIRLANAN MİR- 132 VE TRANSFORME EDİCİ BÜYÜME FAKTÖRÜ-ß3 YÜKLÜ LİPOZOM İÇEREN DUAL ETKİLİ KİTOSAN HİDROJEL İSKELELERİNİN TEDAVİ ETKİNLİĞİNİN YANIK YARASINDA DEĞERLENDİRİLMESİ

Abstract

Although mortality rates in burn injuries have decreased, hypertrophic scarring that develops after burns reduces the quality of life of individuals and adversely affects their social participation. In this thesis, the combined use of the anti-inflammatory and pro-angiogenic effects of the miR-132 mimic together with the antifibrotic effect of TGF-β3 was employed to reduce persistent inflammation and TGF-β1-associated scar formation, thereby aiming to accelerate burn wound healing and to promote scarless healing. For this purpose, TGF-β3 was encapsulated into DOTMA/DOPC/CHOL-based cationic liposomes, while the miR-132 mimic was electrostatically complexed with liposomes to prepare lipoplex formulations. To enhance transfection efficiency, the PEGylated formulations were optimized by targeting a particle size of 100–200 nm and a zeta potential equal to or greater than +40 mV. The antifibrotic efficacy of the formulations was evaluated in a fibrosis model induced with TGF-β1 in L929 cells at the gene and protein levels by RT-qPCR and ELISA, respectively. Combined treatment optimized the COL1/COL3 ratio and produced a balanced antifibrotic response in collagen, MMP13, MMP9, RASA1 and cytokine levels. TGF-β3-loaded liposomes and miR-132-loaded lipoplexes were incorporated into chitosan-based hydrogel scaffolds fabricated by 3D printing in order to provide local and controlled release. The optimized hydrogel formulation exhibited appropriate printability and rheological properties; dispersion of the liposomes/lipoplexes within the hydrogel altered the swelling, degradation and mechanical properties, and the structural properties were evaluated by SEM, DSC and FTIR analyses. In the release studies, TGF-β3 release continued over 312 h and reached 96.64%, whereas 9.84% release was obtained from the miR-132 lipoplexes over the same period, with burst release being limited. In a murine burn wound model, the hydrogel scaffold containing miR-132 and TGF-β3 together accelerated wound closure between days 7 and 15 and regulated the COL1/COL3 ratio. Preservation of α-SMA levels in the combination group indicated that myofibroblast activity and contractile capacity were maintained during extracellular matrix remodelling. In conclusion, co-delivery of miR-132 and TGF-β3 from 3D-printed chitosan hydrogel scaffolds via liposome/lipoplex systems was shown to be a promising dual-acting approach for regulating inflammatory and fibrotic processes in burn wounds and for supporting scarless wound healing.