Gene expression of multidrug-resistant ATP-binding cassette transporter (MDR1/ABCB1) in bovine mastitis

Abstract

Purpose: To investigate the expression of multidrug-resistant ATP binding cassette transporter P-glycoprotein (MDR1/ABCB1/P-gp) in mastitis and its correlation with the expression of apoptosis regulation. Methods: Mastitic and normal mammary gland samples were collected after clinical examination and confirmed using field California mastitis test. Total RNA was extracted followed by cDNA synthesis and real-time PCR to detect the expression pattern of P-gp. Tissue sections were examined for pathological changes and immune reactivity to the apoptotic regulator, Bcl-2-associated X protein (BAX). Results: Stained sections from mastitic samples showed congestion, infiltration of inflammatory cells and hemorrhage. Using immunohistochemistry, it was shown that mastitis is associated with overexpression of the apoptosis regulator, Bcl-2-associated X protein (BAX). There was increased expression of the pro-apoptotic factor, Bax, in mastitic alveolar lining and lactic tubules compared with normal mammary gland tissues. Using real-time PCR, the expression level of MDR1/ABCB1 was determined to be 2.6-fold higher in mastitic tissues than in normal mammary tissues. Conclusion: Higher MDR1/P-gp level can modulate drug interventions by preventing intracellular accumulation of chemotherapeutics or anti-inflammatories via continuous efflux or export to extracellular fluids.