Figure 7.

Increased affinity of MPO for oxidized HCASMC-ECM. (A) Decellularized HCASMC-ECM was prepared and exposed to buffer or 5–100 μM HOCl at 37 °C for 2 h, washed, and then incubated with 10 nM of MPO at 37 °C for 30 min. The samples were then washed to remove non-adherent material, before analysis of matrix-bound MPO and HOCl-mediated damage via ELISA using MPO mAb (2C7) and 2D10G9, respectively. In (B), matrix-bound MPO (prepared as described above) was incubated with 50 μM H₂O₂, 200 mM Cl⁻ and 10 mM taurine (to trap HOCl) at 37 °C for 2 h. The resulting taurine chloramines were assayed using TMB (see Materials and methods) with the absorbance recorded at 645 nm. Data from triplicate determinations (n = 3 independent experiments) were analyzed by one-way ANOVA with Tukey’s post-hoc test. * indicates statistical significance from the control (0 μM added HOCl) at the p < 0.05 level, and ** at the p < 0.01 level.