Staphylococcus aureus on the effect of expression of MMPs/TIMPs and uPA system in bovine mammary fibroblasts

Abstract Background Bovine mammary fibrosis is characteristic of chronic in injury in response to diverse pathogens. Staphylococcus aureus (S.aureus) is a frequent cause of mastitis in bovine and is prone to persistent infection. Diverse studies have shown MMPs/TIMPs and uPA system as a potent target for the treatment of fibrosis. However, pathogenesis of S.aureus-induced mammary fibrosis has not been completely defined. Methods BMFBs treated with heat-inactivated S.aureus (105, 106, and 108 CFU/mL) for 6, 12, 24, and 48 h. Total RNA and protein were isolated from the treatments and controls of BMFBs samples. MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, TIMP-1, TIMP-2, COL Ⅰ, uPA, uPAR and PAI-1 gene and protein expression were examined by RT-qPCR and Western blot analysis. Gelatin zymography assay was performed to assess the levels of MMP-2 and MMP-9 enzyme secreted. Results BMFBs treated with heat-inactivated S.aureus increased mRNA and protein expression levels of MMP-1, MMP-2, MMP-3, MMP-9 and MMP-13, and heat-inactivated S.aureus induced TIMP-1, TIMP-2 and COL Ⅰ expression. There was a clear activation of MMP-2 in the presence of heat-inactivated S.aureus in the conditioned medium from the BMFBs, whereas MMP-9 was no significantly altered. Moreover, uPA system was activated in BMFBs to S.aureus. Conclusion Activation of the uPA system together with its impact on the MMPs levels could play a significant role in S.aureus-induced BMFBs with mechanism of ECM metabolism, MMPs/TIMPs and uPA system could participate in bovine mammary fibrosis.