Gallstone formation and gallbladder mucosal changes in mice fed a lithogenic diet

Area of Science:

• Gastroenterology and Hepatology
• Cell Biology
• Pathology

Background:

• Gallstone formation is a prevalent condition with significant health implications.
• Understanding the cellular and tissue-level changes in the gallbladder mucosa is crucial for elucidating gallstone pathogenesis.

Purpose of the Study:

• To investigate the sequential morphologic and cellular changes in gallbladder mucosa during gallstone development.
• To explore the relationship between gallbladder hyperplasia, metaplasia, and cholesterol gallstone formation.

Main Methods:

• A murine model was utilized, feeding 52 mice a lithogenic diet (1% cholesterol, 0.5% cholic acid).
• Gallbladder tissues were analyzed sequentially from 2 days to 40 weeks to evaluate morphologic and cellular alterations.
• Histochemical analysis was performed to characterize mucin profiles in developing mucous cells.

Main Results:

• Cholesterol gallstones formed in mice within 2–8 weeks of diet initiation.
• A significant increase in the mitotic index of gallbladder mucosa was observed early (2 days).
• Progressive hyperplastic changes, including papillary projections and inward proliferation, were noted.
• Appearance and gradual increase of mucous cells with distinct histochemical mucin profiles occurred concurrently with stone formation.
• Metaplastic changes in the gallbladder mucosa were observed in conjunction with gallstone development.

Conclusions:

• Gallbladder mucosal hyperplasia and metaplasia are closely associated with cholesterol gallstone formation.
• Hyperplasia appears to be a reactive response to lithogenic bile or gallstones.
• Metaplasia and cholesterol gallstone development may occur simultaneously and interact synergistically.