Effects of continuous blood purification on Connexin43 in human alveolar epi-thelial cells
AIM: To investigate the effect of continuous blood purification (CBP) on the expression of Connexin43 (Cx43) in human alveolar epithelial cells (AECs) induced by the serum of patients with severe acute pancreatitis (SAP) accompanied with acute lung injury (ALI). METHODS: Fasting serum of healthy volunteers and serum of patients with SAP and ALI at pre-CBP, 6-hour-CBP and 20-hour-CBP were collected, Immunofluores-cence staining and RT-PCR were used to detect the expression of Cx43 and Cx43 mRNA in AECs separately cultured by the serum from different groups for 48 h in vitro. ELISA was used to detect the level of serum TNF-α in each group. RESULTS: Cx43 posi-tive staining in each patient group was significantly less than that in healthy control group. With the increase of the treatment time, the positive staining gradually increased. The relative expression of Cx43 mRNA in pre-CBP group(0.08±0.01) was significantly leas than that in healthy control group (0.57±0.02) (P<0.01). With the increase of the treatment time, the expression gradually increased in 6-hoar-CBP group(0.23±0.02) and 20-hour-CBP group(0.36±0.02) (P<0.01). The level of serum TNF-α in pre-CBP group (59.43±4.50) ng/L was significantly higher than that in healthy control group(16.06±3.68) ng/L(P<0.01). With the increase of the treatment time, the level gradually decreased in 6-hour-CBP group (41.16±3.49) ng/L and 20-hour-CBP group (34.65±3.22) ng/L (P<0.01). The expression of Cx43 mRNA was negatively correlated with the level of TNF-α. CONCLUSION: The decrease of Cx43 in AECs plays a part in the process of SAP patients with secondary ALI. CBP up-regulates the expression of Cx43 by removing TNF-α and thus protects the respiratory function.