Fig. 2

a HAS2 gene expression levels (n = 4) in normal human dermal fibroblasts (NHDF) after stimulation with 1 mg/ml HA, 1.5 U/ml HYAL and HA + HYAL co-stimulation for 2 h, 4 h, 12 h and 24 h; b HAS2 gene expression levels of NHDF after stimulation with 15 U/ml, 1.5 U/ml, 0.15 U/ml and 0.015 U/ml HYAL for 24 h. c, d HA amount (ng/ml) measurement by means of ELISA (n = 4) in supernatants of NHDF treated as described in a and b. e–k Show representative histological HA-stained sections of human skin samples treated with e control (CTRL) medium, f 1 mg/ml HA, g 15 U/ml HYAL, h 1.5 U/ml HYAL, i 0.15 U/ml HYAL and j 0.015 U/ml HYAL, scale bars = 50 µm. k Quantification of HA-positive staining measured in CTRL, HA and HYAL (15 U/ml, 1.5 U/ml, 0.15 U/ml and 0.015 U/ml) treated skin samples plotted as individual values of n = 4, mean values are shown by the horizontal bar. Asterisks above columns indicate statistical significant differences compared to their respective medium controls, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001 (t-test, two-sided)