Abstract
AIM: To explore the roles of renal cell apoptosis and expression of Bax and Bcl-2 in renal injury in rats with severe acute pancreatitis (SAP).
METHODS: Thirty rats were randomized into sham operation (SO, n = 15) and SAP group (n = 15). The model of SAP was established by retrograde injection of 50 g/L sodium taurocholate into the biliopancreatic duct in the rats. Serum creatinine (Cr) and blood urea nitrogen (BUN) were determined 6, 12, and 18 h after injection. The pathological changes were observed by light and electron microscopy. The apoptosis of renal cells was determined by TUNEL method, and the expression of Bax and Bcl-2 was detected by immunohistochemical staining (SABC assay).
RESULTS: As compared with those in SO group at the same phase, serum Cr and BUN in SAP group increased markedly. Significant injuries of renal tissue were observed under light and electron microscope.The apoptotic index of renal glomerular cells increased significantly 6, 12, 18 h after injection (3.2±1.1 vs 0.8±0.1, P <0.05; 3.9±1.8 vs 0.9±0.1, P <0.05; 4.8±1.7 vs 0.8±0.2, P <0.01, respectively). The apoptotic index of renal tubule cells also increased significantly (9.8±1.1 vs 1.3±0.5, P <0.01; 12.6±2.3 vs 1.2±0.3, P <0.01; 15.7±2.6 vs 1.3±0.3, P <0.01, respectively). The expression of Bax in renal glomerulus and tubule increased significantly at 6, 12, 18 h, respectively (glomerulus: 3.05±0.86 vs 1.01±0.04, P <0.05; 3.37±1.13 vs 1.06±0.05, P <0.05; 4.11±1.24 vs 1.09±0.03, P <0.05; tubule: 8.17±2.16 vs 1.53±0.07, P <0.01; 12.92±1.81 vs 1.61±0.05, P <0.01; 13.08±2.53 vs 1.59±0.05, P <0.01), and increased continuously. Bcl-2 was mainly expressed in the regions of renal tubule, and it also increased in SAP group at 6, 12, 18 h, respectively (3.38±1.07 vs 1.58±0.02, P <0.05; 4.26±1.13 vs 1.59±0.06, P <0.05; 7.21±1.04 vs 1.61±0.02, P <0.01). The level of Bcl-2 expression in renal glomerulus was higher in SAP group than that in SO group at 6, 12, 18 h, respectively (2.18±0.65 vs 1.04±0.02; 2.42±0.63 vs 1.03±0.05, P <0.05; 2.69±0.47 vs 1.08±0.04, P <0.05), but decreased with the duration of the injuries.
CONCLUSION: Renal cell apoptosis, which relates to the up-regulated expression of Bax and downed regulated expression of Bcl-2, may be involved in the pathogenesis of renal injury in patients with SAP.
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