We also found that two biomarkers of the innate immune system, α-defensin-5 (DEF-5) and lipocalin-2 (LCN2), were upregulated at the mRNA level by 5- and 11-fold, respectively, in the colon of Asp-treated AOM-injected rats compared to AOM-controls or saline-injected rats (Fig. 8D). Here, LCN2 is linked to infectious otitis media.