(a), TSG-6 is expressed constitutively at low levels in uninjured skin, and highly induced by wounding. Western blots from wounds; two examples (different mice) are shown for each time point. (b), Quantitation of TSG-6 protein expression from pooled samples, number of mice indicated (n); mean ± SEM; P-values from One-way Repeated Measures ANOVA. (c), Analysis of HC-HA in skin lysates on an acrylamide gel. HC proteins covalently bound to HA in HC-HA complexes are located at the top of the gel (boxed band, Lane 3). HC is released from complexes by degradation of HA with Streptomyces hyaluronidase (Hy’ase). Note that HC-HA levels are significantly higher in wounds (Lane 4) than in unwounded skin (Lane 2). (d), Quantitation of the HC band from 3 gel experiments; P-value, Student t test. (e) Gel analysis of HC-HA complexes in unwounded skin and in 24-hour excisional wounds, confirming that the amount of HC bound to HA is increased in wounds relative to intact skin (blue boxes). HA-bound HC is completely absent in TSG-6 null mouse skin, whether intact or wounded (dashed red boxes).