To observe the promoting effect of pulsed shortwave therapy on wound healing in pediatric patients with upper limb burns and explore its underlying mechanisms.

A total of 40 children with deep Ⅱ°upper limb burns treated in our hospital from June 2021 to June 2023 were enrolled, and randomly divided into a control group and an observation group, with 20 cases in each group. The control group received conventional dressings, and the observation group received conventional dressings combined with pulsed shortwave therapy. The wound healing time, first appearance of skin islands on the wound, and initial number of skin islands were observed and recorded using a camera. The proportion of granulation tissue area in the wound was observed using eKare inSight 3D. The positive rate of wound bacteria was detected by collecting wound secretions for bacterial culture examination. Blood flow perfusion on the wound was measured using a blood flow meter.

The observation group showed significantly faster wound healing and initial appearance of epithelialization (P<0.05), and obviously higher rate of granulation tissue growth than the control group (P<0.05). Moreover, the observation group demonstrated better control of bacterial infection in the wounds than the control group (P<0.05). Blood flow measurement results revealed no significant increase in blood flow perfusion after pulsed shortwave therapy in the observation group (P>0.05). However, with the elapse of time, both groups exhibited an increasing trend in blood flow perfusion (P<0.05).

Pulsed shortwave therapy effectively promotes wound healing in pediatric patients with burns, by facilitating necrotic tissue clearance and granulation tissue regeneration, which may be associated with its non-thermal effects.

To investigate the histological differences and expression of E-cadherin, Vimentin, matrix metalloprotein-9 (MMP-9), TNF-α, dipeptidyl-peptidase 4 (DPP4, also called CD26) in the margin and center of hypertrophic scar, superficial dilated keloid and normal skin.

Ten patients with keloid and another 10 with hypertrophic scar undergoing excision surgery in our hospital from October 2020 to August 2021 were included, and 8 cases requiring partial normal skin resection were also recruited. The resected tissues were collected, the tissue morphology was observed with HE staining, and the expression levels of E-cadherin, Vimentin, MMP-9, TNF-α and CD26 were detected by immunohistochemical staining and Western blotting.

The E-cadherin expression in the epidermis of both keloid and hypertrophic scar was significantly lower than that of normal skin (P<0.05), and the level in the edge of keloid was obviously weakened as compared with that of the center (P<0.05), but there was no significant difference between the edge of hypertrophic scar and the center (P>0.05). By contrast, the expression levels of Vimentin, MMP-9, TNF-α and CD26 in the epidermis of both keloid and hypertrophic scar were remarkably enhanced when compared with those of normal skin (P<0.05), and the keloids' edge higher than the center (P<0.05), while no significance between the hypertrophic scars' edge and center (P>0.05).

The differences in epithelial-to-mesenchymal transition (EMT) and expression of relevant biomarkers within individual scars may be one of the reasons for the diversity of clinical features between hypertrophic scar and keloid, in which TNF-α and CD26 may be the key factors.