Fig. 5

Histopathological sections on day 14 in different groups (10x magnification); control (lack of proper epithelium formation (black star), edema (blue arrow) and hemorrhage (white star); CsD (chitosan containing doxycycline; formation of thin epithelium (black star), edema (blue arrow) and the absence of dense and regular collagen fibers (white arrow), hyperemia (white star); CsDZn (chitosan containing doxycycline and zinc nanoparticles; formation of thin epithelium (black star), fine collagen fibers (white arrow); CsZnS (chitosan containing doxycycline and selenium nanoparticles; formation of delicate epithelium (black star), edema (blue arrow), absence of regular collagen fibers (white arrow), inflammation (red arrow); CsDZnS (chitosan containing doxycycline and zinc nanoparticles, and selenium nanoparticles; formation of thick and unified epithelium (black star) and surface keratin (red star), relatively dense connective fibers in the dermis (white arrow)