We investigated changes of serum lipoproteins and pathological observations of the liver in rats with chronic liver injury induced by carbon tetrachloride (CCl
4) . Male, Sprague-Dawley, 6 week old, 150-170g rats were used in the experiment. CCl
4 was dissolved in olive oil, and 2 ml/kg body weight was given to each animal. Chronic liver injury was produced in rats by oral administration of 0.5 ml/kg CCl
4 twice weekly for 10 weeks. Rats were sacrificed after 5 (5W-CCl
4) and 10 (10W-CCl
4) weeks of CCl
4 administration, and the serum and livers were collected. In the 5W-CCl
4 group, these was increase of high density lipoprotein subfractions (HDL
1, HDL
2, HDL
3) and low density lipoprotein (LDL) . Increased HDL
1 and LDL, and decreased very low density lipoprotein (VLDL) were also evident in the 10W-CCl
4 group. The lipid content in HDL and LDL fractions were increased by CCl
4 and the total protein (TP) content was decreased in the HDL. Decrease of lipid and TP content in VLDL, were also evident in the 10W-CCl
4 group. Increases of total cholesterol and triglyceride, and decrease of phospholipid (PL) in the liver were observed in the 5W-CCl
4 group. PL in the liver was also decreased by 10W-CCl
4. Pathological examination of the livers revealed that CCl
4 caused the formation of septum and pseudolobules by the proliferation of connective tissue. Lipid deposition in the pseudolobule of the liver was caused by 5W-CCl
4. Loss of cytoplasm and nuclei, vacuolation and necrosis in the pseudolobular hepatocytes, but no lipid deposition were caused by 10W-CCl
4. The results suggest that the increase of HDL and LDL by 5W-CCl
4 was due to damage of lipoprotein metablolism in the liver associated with liver injury, and decrease of VLDL and increase of HDL
1 and LDL by 10W-CCl
4 were due to defective lipoprotein metabolism, and lipoprotein formation.
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