Figure 9.

Representative histopathological sections stained with H&E of wound healing on Days 0 and 14 showing comparisons between groups ((A) negative control group; (B) treatment group (TiO₂-NP formulation); (C) positive control group). Note the thin epidermis and dermis above the abundant subcutaneous layer on Day 0 (A–C) compared with Day 14 (A–C). The H&E staining shows collagen fibers—stained pale pink, cytoplasm stained purple, nuclei stained blue, and red blood cells—stained cherry red. The negative control had the thickest layer of epithelium compared to the other groups and showed remarkable vertical collagen formation (14A). The TiO₂ NP formulation was randomly infiltrated with mononuclear cells (MN) and mainly vertical collagen formation (14B). The positive control demonstrates a mixed pattern of collagen fiber formation, infiltration of a moderate number of mononuclear cells (MN), and granulation tissue (14C). The wound exhibits a few to moderate numbers of infiltrating inflammatory cells, the majority of which are neutrophils, and a small number of macrophages and lymphocytes with foci of necrosis, ulceration, and fibrin formation (0A, 0B, 0C). Abbreviations: H&E, Hematoxylin-Eosin; EP, Epidermis, DM; Dermis, SB; Sebaceous gland, BV; Blood vessel, MN; Mononuclear cell infiltration (arrowhead), CL; Collagen fiber orientation (arrowhead).