Early Fibrotic Remodeling Remains Responsive to Autologous Fat Grafting: Histological Findings in a Rat Model

Fibrosis-associated soft tissue remodeling involves progressive alterations in extracellular matrix composition, vascular architecture and tissue biomechanics. Early fibrotic lesions may remain biologically responsive before irreversible sclerosis develops. This study evaluated the histological evolution of bleomycin-induced soft tissue remodeling and the effects of autologous fat grafting in a rat model.

Twenty female Wistar rats received subcutaneous bleomycin (1 mg/kg/day for three consecutive days) to induce localized soft tissue remodeling. Autologous fat grafting was performed 17 days later. Clinical assessment was conducted at baseline, Day 17 and Day 31 using a standardized semi-quantitative score evaluating erythema, edema, skin elasticity, cutaneous mobility and ulceration or necrosis. Histological analysis was performed at predefined timepoints.

Bleomycin induced reproducible early fibrotic remodeling characterized by collagen deposition, stromal hypercellularity, vascular remodeling and architectural distortion. The mean composite clinical score increased from 0 at baseline to 9.10±1.75 on Day 17 and decreased to 7.75±1.35 after fat grafting on Day 31 (p=0.00024). Histological examination demonstrated persistent fibrotic septa, fibroblast proliferation, vascular reorganization and partial integration of grafted adipose tissue, indicating ongoing tissue remodeling.

Bleomycin-induced remodeling produced reproducible early fibrotic changes in dermal and subcutaneous tissues. Autologous fat grafting was associated with significant clinical improvement and histological evidence of continued tissue reorganization. This model supports investigation of regenerative therapies targeting early fibrosis-associated soft tissue remodeling.