Fig. 4: MMP-9 is crucial for NTEM.

A Representative flow cytometry images displaying neutrophil infiltration in epidermis and dermis in MMP inhibitor or vehicle-treated group in the ICD model. B the ear thickness was measured 24 h post ICD conduction in the MMP inhibitor or vehicle-treated group. C, D Quantitative data of epidermal/dermal infiltrated neutrophil counts (10⁴) in A, n = 9, means ± SEM. E Quantitative data of epidermal/dermal infiltrated neutrophil ratio (NTEM ratio) in MMP inhibitor or vehicle-treated group. F Representative flow cytometry images of neutrophil infiltration in epidermis and dermis in Mmp9-competent and Mmp9-deficient mice in the ICD model. G The ear thickness was measured 24 h post ICD conduction in the Mmp9-deficient and WT mice. H, I Quantitative data of epidermal/dermal infiltrated neutrophil counts (10⁴) in (G) means ± SEM. J Statistical flow cytometry analysis of NTEM ratio in (G) n = 9, means ± SEM. K Upper panel: representative gelatin zymography of PBS-Lipo-treated skin lysate. Lower panel: Clod-Lipo-treated skin lysate. L Quantification of gelatin zymography in (K). n = 6, means ± SEM. M qPCR analysis of Mmp9 mRNA expression of cells infiltrated in the dermis. n = 4-9, means ± SEM. N qPCR analysis of Mmp9 expression in PBS-Lipo or Clod-Lipo-treated skin. n = 6, means ± SEM. Data are representative of two independent experiments in (K–N). All the mice were female for these experiments. Data are representative of three independent experiments in (B–J). Statistical analysis was performed using a two-tailed unpaired Student’s t-test in (B–E, G–K). Data in M were analyzed using one-way ANOVA followed by Bonferroni’s post hoc test. Bonferroni-corrected p values are indicated in (M).