Low salt stimulates the expression of cyclooxygenase-2 and its relationship to p38 MAPK signal transduction in a mouse macula densa cell line / 中华肾脏病杂志

ABSTRACT

Objective To evaluate the role of low salt (LS) medium and the involvement of p38 mitogen-activated protein kinase (p38 MAPK) in the expression of cyclooxygenase-2 (COX-2) and production of PGE2 in a mouse macula densa derived cell line (MMDD1 cells). Methods Confluent MMDD1 cells were exposed to serum free DMEM/F12 in a 11 mixture with normal saline (NS), 300 mmol/L mannitol (to reduce NaCl to half, LS solution). Semi-quantitive reverse transcription and polymerase chain reaction amplication (RT-PCR) and Western blotting were used to detect the expression of COX-2 mRNA and protein with LS solution. The content of PGE2 in the supernatant was examined by enzyme linked immunosorbent assay (ELISA). Expression of total and phosphorylated p38 MAPK kinsae was examined by Western blotting in LS solution. Results The COX-2 mRNA abundance and protein expression of MMDD1 cells were up-regulated in LS group as compared to NS group (16 h mRNA 0.94?0.12 vs 0.26?0.09, 28 h protein 0.59?0.02 vs 0.25?0.07, rspectively, all P