Differential proteomics research on gallbladder bile samples from two kinds of cholelithiasis patients

Objective By comparing gallbladder bile samples from cholesterol cholelithiasis patients with pigment cholelithiasis patients, we try to find out proteins participating in gallstone formation for revealling two kinds of stone formation mechanisms. Methods Gallstones and bile were collected from cholelithiasis patients. These patients were divided into two groups by stone chemical compositon analysis.Patients with stone cholesterol levels greater than 70% were assigned into cholesterol stone group, and those with bilirubin levels greater than 40% into pigment stone group. After removing the bile salt and lipid, peptide fragments were separated by 2D-LC, analysed by MS/MS, and searched against Swiss Prot database by Mascot. Results There were 495 and 511 proteins identified from cholesterol stone group and pigment stone group respectively. There was 1 anti-nucleation factor and 12 pro-nucleation factors, including 2 proteins up-regulated in cholesterol stone group and 11 proteins down-regulated in pigment stone group. Conclusion 2D-LC/MS/MS is an efficient technology in bile proteomics research. Differentially expressed proteins reveal 2 kinds of different stone formation mechanisms. Pro-nucleation factors are closely related with pigment stone formation, while down-regulation of apolipoprotein A- I is closely related with cholesterol stone formation. Key words: Gallstone;  Bile;  Proteomics