# Effect of Hexagonal Boron Nitrides Injection on the Survival of Dorsal Pedicle Skin Flap in Rats: An Experimental Study

## TL;DR

Injecting hexagonal boron nitride (hBN) during skin flap surgery in rats improved flap survival, possibly by supporting tissue healing and cell proliferation.

## Contribution

This study experimentally demonstrates that hBN injection enhances dorsal pedicle skin flap survival in rats.

## Key findings

- hBN injection improved epithelial and collagen structure in skin flaps compared to controls.
- Mast cell density was higher in saline-injected flaps but not in hBN-treated ones.
- No significant differences in TGF-β1 and MMP-1 levels were observed across groups.

## Abstract

Background: Dorsal pedicle skin flap application is a cover procedure frequently used by plastic surgeons to cover acute and chronic wounds, but preventing postoperative flap loss and disruption of the wound healing process has not yet been achieved. Injecting boron nitride during the transfer of the dorsal pedicle skin flap may increase flap survival. Objective: This study investigated the efficacy of hexagonal boron nitride (hBN) injection in enhancing the survival of pedicled skin flaps harvested from the dorsal region of rats. Method: This study employed an experimental design. A total of 24 Wistar albino rats were divided into three groups of eight each: Control (Group 1), Sham (Group 2), and Experimental (Group 3). A 27 cm2 (3 cm × 9 cm) dorsal skin flap with a proximal pedicle was harvested at the level of the iliac crests, with the flap extending cranially, and then reattached. During flap transfer, no intervention was performed in Group 1, physiological saline was injected into Group 2, and hBN was injected into Group 3. After a certain period of time, sections were taken from the proximal pedicle skin flap on the dorsal side of the rats, and histochemical examination and biochemical analyses were performed on these sections. Results: In this study, it was observed that the epithelial integrity of the epidermal layer was disrupted and the epithelium was thinned in places in Group 2. Compared to Group 1, collagen fiber density was lower, collagen fiber arrangement was irregular, and mast cell density was higher. In Group 3, similar to Group 1, the epidermis and dermis layers were composed of multilayered flat keratinized epithelium, collagen fiber density was high and had a regular arrangement, and elastic fiber structure was of normal density. The TGF-β1 and MMP-1 measurement results for the three groups were compared, and no statistically significant difference was found between the groups (p > 0.05). Conclusions: The results of this study support the benefit of hBN injection in improving flap survival after proximal pedicle skin flap application on the dorsal side of rats. Although the improved healing of skin layers after flap transfer with hBN suggests that it supports cell proliferation, the mechanism of action and pathophysiology remain unclear.