Expression and its significance of caveolin–1 in liver and gallbladder of gallstone mice model

Abstract

Objective To investigate the role and possible mechanism of caveolin–1 (CAV1) in the forming of cholesterol gallstone in mice fed with lithogenic diet. Methods Cholesterol gallstone susceptible C57BL/6 mice were study objects. The mice of control group (n=6) and experiment group (n=6) were fed with normal diet and lithogenic diet for four weeks respectively. The condition of cholesterol gallstone forming, changes of serum lipid and bile composition were measured, and the expressions of CAV1 and scavenger receptor classB member Ⅰ (SR–BⅠ) at mRNA and protein level in the liver and gallbladder were detected by realtime–polymerase chain reaction and Western blot, respectively. The t test was performed for mean comparsion between the two groups. Results The incidence rate of gallstone in experimental group was 100% after fed with lithogenic diet for four weeks, the lipid level significantly increased, and the proportion of cholesterol in bile raised and bile salt decreased. Compared with those of control group, the expressions of CAV1 at mRNA and protein level in the liver and gallbladder tissues siginificantly decreased (in liver tissue, mRNA 0.53±0.13 vs 1.00±0.32, t=3.330, protein level 0.39±0.07 vs 0.92±0.06, t=10.280; in gallbladder tissue, mRNA 0.40±0.22 vs 1.00±0.22, t=3.823, protein level 1.04±0.07 vs 1.34±0.04, t=6.367, all P<0.01). There was no significant difference in the relative expression of SR–BⅠ at mRNA and protein level in the liver and gallbladder tissues between the mice of experiment group and control group. Conclusion The changes of CAV1 expression at mRNA and protein level in liver and gallbladder tissues may affect lipids metabolism and cholesterol transportation in liver and gallbladder tissues of experiment mice, which might play an important role in the formation of cholesterol gallstone. Key words: Cholesterol gallstone disease; Lithogenic diet; Caveolin–1; Scavenger receptor class B member 1