MMP3 and bacterial urinary tract infection: To explore the ECM change by phenotype, in addition to immunofluorescence analysis, we also examined the secretion of catabolic proteinases in IL-1β-induced NP cells via ELISA, and the results revealed that pretreatment with UTI could also mitigate the increased expression of MMP3/13 induced by IL-1β in a concentration-dependent dose and that the protein expression of collagen type II and aggrecan were also improved by UTI, while NP cells were injured by IL-1β (Figure 4(e)).