Photobiomodulation and Sericin in the Treatment of Second-Degree Burns Induced in Wistar Rats

This study investigated the isolated and combined effects of sericin and low-level laser photobiomodulation (PBM) on the healing of experimentally induced second-degree burns in male Wistar rats. Sericin has previously been associated with enhanced fibroblast migration and improved reepithelialization, while PBM has shown anti-inflammatory potential. To assess their therapeutic value, 60 rats were randomised into six groups: untreated control (CON), silver sulfadiazine (SUL), sericin cream (SER), PBM alone, SUL + PBM and SER + PBM. Burn injuries were produced using a heated metal instrument applied for 3 s, and animals were euthanized 14 days later. Macroscopic photography, photothermography and histomorphometric analyses were performed. Statistical tests using generalised linear models were set at p = 0.05. A significant temperature difference between initial (AV0) and follow-up (AV1) evaluations was observed, although granulation tissue formation did not differ across groups. Collagen analysis revealed that SER, PBM, SUL + PBM and SER + PBM groups presented higher collagen scores than controls (p < 0.05). The SER + PBM treatment was particularly effective, showing the greatest proportion of type I collagen and statistical superiority over the other interventions (p < 0.05). Molecular evaluations demonstrated reduced levels of tumour necrosis factor alpha, thiobarbituric acid reactive substances and catalase, especially in groups receiving PBM in combination with either sericin or sulfadiazine, suggesting a decrease in oxidative stress. Overall, the results indicate that both sericin and PBM positively influence tissue repair, with combined therapy-particularly SER + PBM-yielding enhanced collagen deposition and biochemical markers consistent with improved healing. Further studies are warranted to clarify the underlying biological mechanisms driving these outcomes.