摘要
AIM:To determine the platelet-activating factor (PAF) synthesis and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis. METHODS:Kupffer cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium overnight. PAF saturation binding, ET-1 saturation and competition binding were assayed. ET-1 induced PAF synthesis, mRNA expression of PAF, preproendothelin-1, endothelin A (ETA) and endothelin B (ETB) receptors were also determined. RESULTS:A two-fold increase of PAF synthesis (1.42 ± 0.14 vs 0.66 ± 0.04 pg/μg DNA) and a 1.48-fold increase of membrane-bound PAF (1.02 ± 0.06 vs 0.69 ± 0.07 pg/μg DNA) were observed in activated Kupffer cells of cirrhotic rats. The application of ET-1 to Kupffer cells induced PAF synthesis in a concentration-dependent manner in both cirrhotic and normal rats via ETB receptor, but PAF synthesis in the activated Kupffer cells was more effective than that in the normal Kupffer cells. In activated Kupffer cells, PAF receptor expression and PAF binding capacity were markedly enhanced. Activated Kupffer cells raised the [125I]-ET-1 binding capacity, but changed neither the affinity of the receptors, nor the expression of ETA receptor. CONCLUSION:Kupffer cells in the course of CCl4-induced cirrhosis are the main source of increased PAF. ET-1 is involved endogenously in stimulating the PAF synthesis in activated Kupffer cells via ETB receptor by paracrine. ETA receptor did not appear in activated Kupffer cells, which may exacerbate the hepatic and extrahepatic complications of cirrhosis.
AIM： To determine the platelet-activating factor （PAF） synthesis and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis.
METHODS： Kupffer cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium overnight. PAF saturation binding, ET-1 saturation and competition binding were assayed. ET-1 induced PAF synthesis, mRNA expression of PAF, preproendothelin-1, endothelin A （ETA） and endothelin B （ETB） receptors were also determined.
RESULTS： A two-fold increase of PAF synthesis （1.42 ± 0.14 vs 0.66 ± 0.04 pg/μg DNA） and a 1.48-fold increase of membrane-bound PAF （1.02 ± 0.06 vs 0.69 ± 0.07 pg/μg DNA） were observed in activated Kupffer cells of cirrhotic rats. The application of ET-1 to Kupffer cells induced PAF synthesis in a concentration-dependent manner in both cirrhotic and normal rats via ETB receptor, but PAF synthesis in the activated Kupffer cells was more effective than that in the normal Kupffer cells. In activated Kupffer cells, PAF receptor expression and PAF binding capacity were markedly enhanced. Activated Kupffer cells raised the [^125I]-ET-1 binding capacity, but changed neither the affinity of the receptors, nor the expression of ETA receptor.
CONCLUSION： Kupffer cells in the course of CCl4- induced cirrhosis are the main source of increased PAF. ET-1 is involved endogenously in stimulating the PAF synthesis in activated Kupffer cells via ETB receptor by paracrine. ETA receptor did not appear in activated Kupffer cells, which may exacerbate the hepatic and extrahepatic complications of cirrhosis.
基金
the Major Science and Technology Research Fund of the National 863 Program, No. 2003AA208106
the Fund for Outstanding Medical Scientists of PLA, No. 04J020
关键词
肝硬化
症状
动物模型
临床治疗
Platelet activating factor
Kupffer cells
Receptor
Cirrhosis
