Donors with a serum sodium concentration of>155 mmol/L are extended criteria donors for liver transplantation(LT).Elevated serum sodium of donors leads to an increased incidence of hepatic dysfunction in the early ...Donors with a serum sodium concentration of>155 mmol/L are extended criteria donors for liver transplantation(LT).Elevated serum sodium of donors leads to an increased incidence of hepatic dysfunction in the early postoperative period of LT;however,the exact mechanism has not been reported.We constructed a Lewis rat model of 70%hepatic parenchymal area subjected to ischemia-reperfusion(I/R)with hypernatremia and a BRL-3A cell model of hypoxia-reoxygenation(H/R)with high-sodium(HS)culture medium precondition.To determine the degree of injury,biochemical analysis,histological analysis,and oxidative stress and apoptosis detection were performed.We applied specific inhibitors of the epithelial sodium channel(ENaC)and Na^(+)/Ca^(2+) exchanger(NCX)in vivo and in vitro to verify their roles in injury.Serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),and lactate dehydrogenase(LDH)levels and the area of hepatic necrosis were significantly elevated in the HS+I/R group.Increased reactive oxygen species(ROS)production,myeloperoxidase(MPO)-positive cells,and aggravated cellular apoptosis were detected in the HS+I/R group.The HS+H/R group of BRL-3A cells showed significantly increased cellular apoptosis and ROS production compared to the H/R group.The application of amiloride(Amil),a specific inhibitor of ENaC,reduced ischemia-reperfusion injury(IRI)aggravated by HS both in vivo and in vitro,as evidenced by decreased serum transaminases,inflammatory cytokines,apoptosis,and oxidative stress.SN-6,a specific inhibitor of NCX,had a similar effect to Amil.In summary,hypernatremia aggravates hepatic IRI,which can be attenuated by pharmacological inhibition of ENaC orNCX.展开更多
Na+ transport occurs across many epithelial surfaces and plays a key role in regulating salt and water absorption. The molecular pathway underlying this Na+ transport is the epithelial Na channel (ENaC), which is stri...Na+ transport occurs across many epithelial surfaces and plays a key role in regulating salt and water absorption. The molecular pathway underlying this Na+ transport is the epithelial Na channel (ENaC), which is strictly determined by a variety of hormones like aldosterone, ADH and glucocorticoids. In this study, we found that stimulation of either aldosterone or dexameth- asone (Dex) distributed ENaC channel on the apical membrane of mouse cortical collecting duct cells (M1). In the single channel recordings from excised membrane, high density ENaC was found in the cell with a dome shape by the treatment of either dex or aldosterone. However, low active ENaC was revealed in intact cells treated with dex, when compared to cells treated with aldosterone. Only 5.84% of cells treated with dex containing ENaC exhibited ENaC current transition in the cell-attach recording, whereas 40% of cells treated with aldosterone containing ENaC exhibited ENaC current transition. ENaC currents appeared rapid rundown within 5 min-utes since formation of inside-out configuration in cells treated with aldosterone but not with dex. SKF-525A, a general antagonist of CYP, failed to significantly enhance ENaC activity in intact cells treated with dex, but EGTA, which deforming the cells, increased the ENaC activity in the cells treated with dex. PTX, an antagonist of G-protein, reversed the effect of aldosterone on number of active ENaC in intact cells. Based on our obser-vation, we concluded that there are different mechanisms in regulation of ENaC activity be-tween stimulation of aldosterone and glucocor-ticoids. The activation of G-protein is required to maintain the activity of ENaC in the collecting ducts.展开更多
基金supported by the Funding for Scientific Research and Innovation Team of The First Affiliated Hospital of Zhengzhou University(No.ZYCXTD2023007),China.
文摘Donors with a serum sodium concentration of>155 mmol/L are extended criteria donors for liver transplantation(LT).Elevated serum sodium of donors leads to an increased incidence of hepatic dysfunction in the early postoperative period of LT;however,the exact mechanism has not been reported.We constructed a Lewis rat model of 70%hepatic parenchymal area subjected to ischemia-reperfusion(I/R)with hypernatremia and a BRL-3A cell model of hypoxia-reoxygenation(H/R)with high-sodium(HS)culture medium precondition.To determine the degree of injury,biochemical analysis,histological analysis,and oxidative stress and apoptosis detection were performed.We applied specific inhibitors of the epithelial sodium channel(ENaC)and Na^(+)/Ca^(2+) exchanger(NCX)in vivo and in vitro to verify their roles in injury.Serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),and lactate dehydrogenase(LDH)levels and the area of hepatic necrosis were significantly elevated in the HS+I/R group.Increased reactive oxygen species(ROS)production,myeloperoxidase(MPO)-positive cells,and aggravated cellular apoptosis were detected in the HS+I/R group.The HS+H/R group of BRL-3A cells showed significantly increased cellular apoptosis and ROS production compared to the H/R group.The application of amiloride(Amil),a specific inhibitor of ENaC,reduced ischemia-reperfusion injury(IRI)aggravated by HS both in vivo and in vitro,as evidenced by decreased serum transaminases,inflammatory cytokines,apoptosis,and oxidative stress.SN-6,a specific inhibitor of NCX,had a similar effect to Amil.In summary,hypernatremia aggravates hepatic IRI,which can be attenuated by pharmacological inhibition of ENaC orNCX.
文摘Na+ transport occurs across many epithelial surfaces and plays a key role in regulating salt and water absorption. The molecular pathway underlying this Na+ transport is the epithelial Na channel (ENaC), which is strictly determined by a variety of hormones like aldosterone, ADH and glucocorticoids. In this study, we found that stimulation of either aldosterone or dexameth- asone (Dex) distributed ENaC channel on the apical membrane of mouse cortical collecting duct cells (M1). In the single channel recordings from excised membrane, high density ENaC was found in the cell with a dome shape by the treatment of either dex or aldosterone. However, low active ENaC was revealed in intact cells treated with dex, when compared to cells treated with aldosterone. Only 5.84% of cells treated with dex containing ENaC exhibited ENaC current transition in the cell-attach recording, whereas 40% of cells treated with aldosterone containing ENaC exhibited ENaC current transition. ENaC currents appeared rapid rundown within 5 min-utes since formation of inside-out configuration in cells treated with aldosterone but not with dex. SKF-525A, a general antagonist of CYP, failed to significantly enhance ENaC activity in intact cells treated with dex, but EGTA, which deforming the cells, increased the ENaC activity in the cells treated with dex. PTX, an antagonist of G-protein, reversed the effect of aldosterone on number of active ENaC in intact cells. Based on our obser-vation, we concluded that there are different mechanisms in regulation of ENaC activity be-tween stimulation of aldosterone and glucocor-ticoids. The activation of G-protein is required to maintain the activity of ENaC in the collecting ducts.
