T4 promotes human skin re-epithelialisation.

(a-d) Haematoxylin and eosin histochemistry: overview of wounded human skin fragment. After 3 days, epithelial tongue areas (blacked dotted line area) (ET) and length (blue dotted line) were significantly greater after treatment with T4 compared to control alone. (e-h) Cryosections of control-, or T4-treated human skin were examined by Ki-67 (red arrow)/TUNEL (green arrow) double-labelling [19, 23, 24, 56, 57] (e, f). The percentage of positive cells was analyzed in the new ETs (see dotted line). When compared to the control group, more Ki-67 positive cells after 3 day culture with 1000 nM T4 treatment (and more TUNEL positive cells at day 3 in T4 1000 nM treated group were found, although the differences were not statistically significant (e-h). (i, j) CK6 expression was significantly upregulated by T4, especially in the 1000 nM treatment group. Green fluorescence staining represented cytokeratin 6 IR in the new wound ET (dotted line area).(k, l) MTCO1 expression was significantly up-regulated by T4. Brown staining represents MTCO1 IR in the new ET. Staining intensity was measured in a defined reference area (dotted line) and normalized to the control (100%), as for CK6 expression. Number of independent experiments: n = 3 subjects (i.e. 1–2 punches per patient, per treatment group and per time point and at least 8 photomicrographs were analysed per condition); data were pooled since the results trends in all three independent experiments were comparable). *pp<0.01, ***<0.001. Scale bars = 50μm.