RESUMO
Introduction: The morphology and tissue response to macro- and micro-fat grafting have been widely studied in both clinical and experimental settings; the histological effects of the nanofat graft, however, remain largely unexplored. Aims: This study was carried out to evaluate the histological changes leading to scar rejuvenation in a fine scar following nanofat grafting. Materials and Methods: This was an experimental study carried out on guinea-pig fine-line scar models. Nanofat prepared from abdominal fat of the animal was injected into scar on right legs (NFG) at 1 month whereas left acted as controls (CG). Punch biopsies from all scars were analyzed at 2, 4, and 6 months by Hematoxylin&Eosin, Masson's trichrome, and Picrosirius red stains to evaluate dermal/epidermal regeneration, collagen fiber orientation, pattern of distribution, and amount of mature and immature collagen. Results: Nine animals were included in the final analysis of the study. On histological analysis, the amount of inflammatory infiltrate, collagen fiber orientation, pattern and total histological score at 2, 4, and 6 months were similar between the groups. There was an increased trend for earlier appearance of organized and mature forms of collagen in the NFG group. The distribution of collagen was similar at 2 months; however, there was a significant increase in collagen distribution in NFG at 4 months (NFG: 46.11±11.6, CG: 31.16±9.9; P = 0.010) and at 6 months (NFG: 63.48± 6.6, CG: 49.9 ±8.8; P = 0.002). Conclusion: Nanofat grafting is associated with an accelerated and increased production of mature collagen with proper alignment in fine-line scars.