Fig.6 Pathological examination of wound tissue — Masson’s Trichrome staining of Tissue
Type I and Type III proteins have their main distribution in the dermis, while Type IV and Type VII are chiefly located within the subcutaneous tissue [47-50]. Before delving into a specific analysis of the collagen types and their distribution in samples at various time points as represented in Fig. 7, an elementary examination was conducted on the Sirius Red-stained microstructure under a 400x magnification. Initially, on the third day subsequent to the initial laser welding, sporadic deposition of COL-1 fibers around the wound was observed, with the most considerable being in the 90° laser group. After the application of the second laser welding, the groups subjected to deflected laser incident angles presented a significantly greater COL-I fiber deposition compared to the 90° laser group. This observation suggests that following two instances of laser welding, the wound area in the 90° laser group had become more supple and softer. COL-1 fibers, which are densely aligned and relatively rigid, offer structural support, whereas COL-3 fibers contribute to the flexibility of the tissue, primarily affecting the skin’s softness. In normal tissues, the Type I to Type III collagen ratio typically fluctuates between 1:1 and 2:1. Any significant deviation from this range may suggest instability in the skin’s collagen structure [51-52].