Kidney morphology and renal expression of aquaporins 2, 3 and 4 during cerulein – Induced chronic pancreatitis in pigs

Purpose

Chronic pancreatitis (CP) is associated with serious complications and reduced quality of life. Kidney failure is a frequent complication of acute pancreatitis (AP), however limited information is available regarding the impact of CP on this condition. In the kidney, 9 aquaporins (AQPs) are expressed to maintain body water homeostasis and concentrate urine. The purpose of this study was to morphologically assess and analyze the location and expression of AQP2, AQP3 and AQP4 and determine whether CP affects renal structure and expression of AQPs in collecting duct (CD) principal cells.

Materials/methods

CP was induced in domestic pigs through intramuscular injections of cerulein (1 ​μg/kg ​bw/day for 6 days; n ​= ​5); pigs without CP (n ​= ​5) were used as a control group. Kidney samples were collected 6 weeks after the last injection and subjected to histological examination. Expression of AQPs was determined by immunohistochemistry and Western blot.

Results

The kidneys of animals with CP exhibited moderate changes, including glomerular enlargement, increased collagen percentage, numerous stromal erythrorrhages and inflammatory infiltrations compared to control group. Although the total abundance of AQP2 in the CD decreased in pigs after cerulein administration, the difference was not statistically significant. Expression of AQP3 and AQP4 was limited to the basolateral membrane of the CD cells. AQP4 abundance remained relatively stable in both groups, while AQP3 expression increased nearly three-fold in pigs with CP.

Conclusion

This study identified morphological alterations and a statistically significant increase in the expression of renal AQP3 when pigs developed CP.