Figure 2.

Photomicrography (hematoxylin and eosin) of colon samples from different experimental groups. Mucosa (m), tubular glands (white arrows), blood vessels (black arrow), submucosa (sm) and edema (e). In A (non-colitic group): the mucosa (m) contains numerous straight tubular glands (white arrows) with many lightly stained goblet cells; the crypt (black arrow), submucosa (sm) and luminal epithelium was intact with a typical morphology; In B (TNBS control group): tubular glands (white arrows) were reduced and the goblet cells were atypical; a disruption with extensive edema (e) and blood vessels (black arrow) can be observed. In PACO₂-treated groups, colon cytoarchitecture was recovering and included the restoration of tubular glands (white arrows) containing goblet cells, especially at the doses of 50 mg/kg (D) and 100 mg/kg (E); edema (e) was significantly reduced in animals treated with at doses of 50 mg/kg (D) and 100 mg/kg (E) and in a lower proportion in animals treated with doses of 25 mg/kg (C), when compared to the TNBS control group (B).