The concentrations of MPO in the soluble fraction of uterine aspirates were quantified with commercially available ELISA kit (Abcam, catalog number ab119605) according to the manufacturer´s protocol. As no results are available regarding the levels of these proteins in uterine aspirates, samples were diluted using five serial dilutions: 1:2, 1:10, 1:50, 1:300, 1:1500.
The same amount of total protein from 8 uterine aspirates was loaded in each well. All samples were assayed in duplicates using a microplate reader and values were reported as ng/mL. The mean absorbance for each set of duplicate standards and samples was calculated. The standard curve was plotted in a log10-log10 scale (see figure 1A). The CV (%) between the duplicates of the samples ranged from 4-13% (average of 7%). Concentration of MMP9 of uterine aspirates ranged from 2 to 1053 ng/ul (see figure 1B).