Triamcinolone Acetonide Suppresses Keloid Formation Through Enhancing Apoptosis in a Nude Mouse Model

Current understanding of steroid treatments for keloids is in regards to modulation of inflammation, proliferation, and apoptosis, with no in vivo study on the latter. Using a nude mouse model, we investigated whether triamcinolone acetonide (TA) injections induce keloids regression through enhancing apoptosis.Thirty-six keloid specimens (1 × 1 cm) were harvested from 6 patients and separated into sets of 2 from the same patient: no treatment and intralesional TA injection (0.4 mg/mL/kg) at 8 weeks of postimplantation. One set was implanted in each of 18 randomly selected nude mice, which were separated into 3 groups based on time of keloid harvesting after treatment: group A, 2 weeks; group B, 8 weeks; and group C, 14 weeks. Each group had 1 set of specimen from each patient. Histological staining was performed with hematoxylin and eosin stain. Immunohistochemistry staining was performed for human-prolyl 4-hydroxylase (hPH4) and caspase 3 protein, along with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay.All keloid specimens survived, with no noted overgrowth. Hematoxylin and eosin staining revealed dense extracellular matrix and viable fibroblasts, and hPH4 immunohistochemistry revealed strong expression, demonstrating keloid viability. Caspase 3 protein and TUNEL expressions were significantly increased in the treatment versus control groups, demonstrating that TA injections induced apoptosis.Triamcinolone acetonide intralesional injections significantly increased apoptosis in keloids, represented by increased caspase 3 protein and TUNEL expressions, supporting that steroids suppress keloids in part owing to enhancement of apoptosis.