Biochemical and physicochemical changes in collagen isolated from the gall bladder of gall stone patients

Abnormal gall bladder motor function with delayed emptying and stasis are the contributory factors of gall stone formation. Since collagen is the major contractile protein, this study was designed to find out whether the biochemical and physicochemical changes of collagen contribute to the pathogenesis of gall stone formation. Collagen was isolated from the gall bladder of 25 gall stone patients undergoing cholecystectomy and from that of 20 gall stone free subjects. The levels of total, soluble and insoluble collagen were determined. The activity levels of collagenase (3.4.23.3) and protease (3.4.24.11) were assessed. Levels of susceptibility of collagen to denaturing agents 2 M potassium thiocyanate and 8 M urea were estimated. Aldehyde content, shrinkage temperature and tensile strength were also determined in isolated collagen. SDS-PAGE was carried out and alpha, beta fractions were quantified. The total and insoluble collagen contents were significantly high in gall stone patients. The activity levels of collagenase and protease were significantly low. Elevated levels of lipid peroxides, aldehyde content, shrinkage temperature and tensile strength were observed in gall stone patients. There is a significant elevation in the beta fraction and a decrease in alpha/beta ratio. Ultramicroscopic structure of gall bladder revealed derangement of collagen fibres and altered tissue architecture. The results showed that the qualitative and quantitative alterations in collagen also contribute for the defective contractility and stasis of gall bladder in gall stone patients.