Neutrophils injure gallbladder interstitial Cajal-like cells in a guinea pig model of acute cholecystitis.

Acute cholecystitis is a common disease with gallbladder dysmotility. Disease pathogenesis involves immune cell infiltration as well as changes in gallbladder interstitial Cajal-like cells (ICLCs). However, it remains unclear if or how the immune cells affect ICLC morphology, density, distribution, and function in gallbladder tissue during acute cholecystitis. In this study, we explored the acute cholecystitis-related alterations in gallbladder ICLCs in a guinea pig model, focusing on the effects of neighboring neutrophils. Adult guinea pigs were randomly divided into four groups (control, 24 hr common bile duct ligation [CBDL], 48-hr CBDL, and antipolymorphonuclear neutrophil [PMN] treated) and analyzed using methylene blue staining and immunofluorescence. Gallbladder contractility was also monitored. To culture gallbladder ICLCs, collagenase digestion was performed on tissue from 10- to 15-day-old guinea pigs. Neutrophils isolated from the peripheral blood of experimental animals 48-hr postsurgery were also cocultured with the gallbladder ICLCs. Intracellular calcium was detected with Fluo-4 AM dye. Our results showed that gallbladder ICLC density significantly declined during acute cholecystitis and was accompanied by shortening of the cellular processes and damage to their network-like structure. However, pretreatment with anti-PMN partially prevented these changes. Gallbladder contraction was also significantly decreased during acute cholecystitis, and this appeared to be mediated by the neutrophils. Moreover, ICLCs cocultured with neutrophils also had shortened and reduced processes and impaired network-like structure formation. Intracellular calcium transient was less sensitive to contraction agonists and inhibitors when cocultured with neutrophils. Taken together, neutrophils greatly affect gallbladder ICLCs and dysmotility during acute cholecystitis.

The Role of Interstitial Cells of Cajal in Acute Cholecystitis in Guinea Pig Gallbladder.

BACKGROUND/AIMS: Acute cholecystitis is common in gallbladder motility disorder. Interstitial cells of Cajal (ICCs) in the gallbladder are involved in the regulation of gallbladder motility. The aim of this study was to explore the change of gallbladder ICCs in acute cholecystitis. METHODS: Thirty adult guinea pigs were randomly divided into 3 groups: a sham-operated group (healthy controls) and 2 study groups. The animals in the study group were subjected to bile duct ligation and then to laparotomy and cholecystectomy at 24 and 48 hours after surgery. Immunohistochemistry, immunohistofluorescence, and laser confocal microscopy were performed to observe the shape, size, morphology, and density of gallbladder ICCs. Western blot and real-time PCR were performed to detect stem cell factor and c-kit protein and mRNA expression, respectively. RESULTS: There were no differences in the shape, size, and morphology of the gallbladder ICCs in the control and the two acute cholecystitis groups. Density of gallbladder ICCs, SCF level, and c-kit protein and mRNA expression all decreased in the acute cholecystitis groups. Further, SCF level and c-kit protein and mRNA expression decreased with progress of acute cholecystitis (all P < 0.05). CONCLUSION: Acute cholecystitis can decrease ICCs through repression of SCF and c-kit expression and that ICCs loss play a role in acute cholecystitis.