Fig. 5.

Histological evaluation of the cold burn wound model and treatment groups (A) Histology of the normal skin featuring all skin layers; epidermis, dermis, hypodermis and thick keratinocytes along with hair follicles (B) Skin adnexa were observed in the wound and healed tissues. In the wound tissue, skin adnexa were distorted, surrounded with inflammatory cells and extravasation of RBCs, however in the healed tissue, there was a specified morphology with HS (hair shaft), IRS (inner root sheath), and ORS (outer root sheath) (C) Comparative histology of all experimental groups at respective time points ie. days 3, 7 and 14. Prominent features are as follows: At day 3: Control: distorted skin adnexa, karryohectic debris, epidermis detachment; hUC-MSCs: tissue distortion, epidermis and dermis attached; Q + hUC-MSCs: skin adnexa started to repair, re-epithelialization; R + hUC-MSCs: partial re-epithelialization. At day 7: Control: hyperplasia of epidermis; hUC-MSCs: re-epithelization, distorted ECM, keratin layer; Q + hUC-MSCs: compact dense fibrous connections; R + hUC-MSCs: partial tissue distortion. At day 14: Control: re-epithelization, tissue distortion; hUC-MSCs: dense fibrous connections, epidermal and dermal attachment; Q + hUC-MSCs: reformed skin adnexa, dense ECM, thick keratin layer, re-epithelization; R + hUC-MSCs: re-epithelization, dense ECM (D) Statistical analysis representing enhanced re-epithelization and granulation at day 14 in all treatment groups, and increased number of skin adnexa per field in Q + hUC-MSC group as compared to control. One-way ANOVA with Bonferroni post-hoc test was performed. Data is represented as mean ± S.E.M (n = 3); p-value ≤ 0.05 was considered statistically significant (where ∗∗∗ = p < 0.001, ∗∗ = p < 0.01, ∗ = p < 0.05).