Postconditioning With Red-Blue Light Therapy Improves Survival of Random Skin Flaps in a Rat Model

Abstract

Background Random skin flap ischemic necrosis is a serious challenge in reconstructive surgery. Photobiomodulation is a noninvasive effective technique to improve microcirculation and neovascularization. Photobiomodulation with red or blue light has been separately proven to partially prevent skin flap necrosis, but the synergistic effect of red and blue light not been elucidated. Our experiment evaluated the impact of postconditioning with red-blue light therapy on the viability of random flaps. Methods Thirty Sprague-Dawley male rats (male, 12 weeks) with a cranially based random pattern skin flap (3 × 8 cm) were divided into 3 groups: control group, red light group, and red-blue light group. On postoperative day 7, flap survival was observed and recorded using transparent graph paper, flaps were obtained and stained with hematoxylin and eosin, and microvessel density was measured. Micro-computed tomography was used to measure vascular volume and vascular length. On days 0, 3, and 7 after surgery, blood flow was measured by laser Doppler. To investigate the underlying mechanisms, the amount of nitric oxide (NO) metabolites in the flap tissue was assessed on days 3, 5, and 7 after surgery. Results The mean percentage of skin flap survival was 59 ± 10% for the control group, 69 ± 7% for the red light group, and 79 ± 9% for the red-blue light group (P < 0.01). The microvessel density was 12.3 ± 1.2/mm2 for the control group, 31.3 ± 1.3/mm2 for the red light group, and 36.5 ± 1.4/mm2 for the red-blue light group (P < 0.01). Both vascular volume and total length in the red-blue light group showed significantly increased compared with the red light and control group (P < 0.01). Blood flow in the red-blue light treated flap showed significantly increased at postsurgery days 3 and 7 compared with the red light and control group (P < 0.01). The level of the NO metabolites was significantly increased in flap tissues belonging to the red-blue light group compared with the other 2 groups (P < 0.01). Conclusions This study showed that postconditioning with red-blue light therapy can enhance the survival of random skin flap by improving angiogenesis and NO releasing.

Nitric oxide-releasing nanoparticles protect human retinal pigment epithelium cells and mice retina from prolonged blue light exposure through antioxidant and vascular enhancement

“…This concern arises because blue light, characterized by shorter wavelengths and more incredible energy than other visible spectrum colors, tends to scatter more within the eye, directly impacting retina cells. This light plays roles in numerous biological processes, from transcriptional activation and gene expression to gene therapy [8,9]. Notably, it has been associated with the generation of ROS [10], direct damage to photoreceptors [11], and the activation of speci c genes such as Cryptochrome (Cry) [12,13], which in turn activates Calcium and Integrin Binding 1 (CIB1) and AKT [14,15].…”