Non-invasive, in vivo fluorescence technique as an objective tool for monitoring wound healing following Low Level Laser Therapy

Collagen represents major protein component of the extracellular matrix (ECM), thus its monitoring could be used as an ideal tool for assessing wound healing following therapy. Presently, there is a great need to develop quick, objective, non-destructive method to monitor collagen synthesis during progression of wound healing. The applicability of the Laser induced fluorescence technique towards wound healing monitoring by measuring collagen levels at different stages of the healing progression is the main idea behind the current work. Six to eight weeks old Swiss albino mice with ccircular wounds of 15 mm diameter were illuminated with single exposure of 2 J/cm² from He-Ne laser (632.8 nm; 7 mW power; 4.02 mW/cm² power density) along with un-illuminated and un-wounded controls. Spectroscopic changes were monitored by recording in vivo fluorescence from each animal (under anesthesia) at different post-wounding days (5^th, 10^th, 30 ^thday) by exciting granulation tissue/skin with 325 nm He-Cd laser. The autofluorescence from the tissue/skin was recorded from four different sites and four spectra were recorded from each site. A total of 2160 spectra were recorded from 45 animals. The in vivo fluorescence studies have shown significant increase (P<0.001) in collagen synthesis upon treatment with optimum laser dose of 2 J/cm² immediately after wounding as compared to un-illuminated control group. It can conclude that in vivo fluorescence measurement is effective in monitoring wound healing and hence could be used over ex vivo method as an objective and non-intrusive method to monitor collagen levels.