Fig. 6

Histological assessment of mucosa thickness and fibrous tissue. (A) Hematoxylin and eosin staining of the wound on Day 3 and Day 7 in the sham group and groups treated with hTMSCs, Hydrogel, and Hydrogel + hTMSCs. Note that by Day 7 complete re-epithelialization and granulation tissue were apparent in the Hydrogel + hTMSCs group. (B) Histological assessment of fibrous tissue in tissue sections stained with MT. Collagen was observed in the areas where the ulcers formed in the hTMSCs and Hydrogel + hTMSCs groups on Day 7 (scale bar = 500 μm). (C) Measurement of the mucosal layer thickness indicates that oral ulcers treated with the hTMSCs and Hydrogel + hTMSCs were the thickest on Day 3. Only the group treated with Hydrogel + hTMSCs showed a significant difference from the Hydrogel and sham group on Day 7. (D) Quantified fibrous tissue (blue stained collagenous tissue) in all groups on Days 3 and 7 based on image analysis of Masson’s trichrome-stained sections. On Day 3, the stem cell treatment yielded the most fibrous tissue formation compared to the sham and the Hydrogel groups. By Day 7, the stem cell-treated group still showed higher fibrous tissue formation but was no longer significantly better than all other groups. P values are indicated as *P < 0.05, *P < 0.05, and **P < 0.01 by one-way ANOVA-Tukey’s multiple comparisons test (n = 4)