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.

Diet supplemented either with dried chicory root or chicory inulin significantly influence kidney and liver mineral content and antioxidative capacity in growing pigs

According to the Regulation No. 1831/2003 of the European Parliament and European Union Council, the use of antibiotics as a dietary supplements has been prohibited. It seems that the administration of prebiotics, instead of antibiotics, into the pig's diet, may regulate the intestinal microbiota and has a long-term health-related impact on the host. Inulin-type fructans can stimulate mineral absorption from the gut. Additionally, it may regulate energy metabolism and activate enzymatic mechanisms preventing oxidative stress. The goal of the present study was to estimate the influence of dietary supplementation with dried chicory root or native chicory inulin on 1) liver histology; 2) liver and kidney lipid metabolism indices, activity of selected enzymes, concentration of macro- and micronutrients and heavy metals; 3) blood plasma, liver and kidney oxidative stress biomarkers and 4) blood plasma water-electrolyte homeostasis indices in growing pigs. The nutritional study was conducted on 24 piglets assigned to 3 dietary groups (n = 8): control (C) fed a basal diet and two experimental groups receiving basal diet supplemented with 2% of inulin (IN) either 4% of dried chicory root (CR). The animals were fed with a group-specific diets for 40 days and then subjected to euthanasia. Subsequently, blood, liver and kidney samples were harvested for further processing. In the control and experimental groups, no apparent morphological abnormalities in the liver tissues were seen. The percent of periodic acid Schiff positive glycogen liver cells was significantly lower in the CR group as compared to C and IN groups (P < 0.001). Chicory root supplementation improved blood plasma prooxidative-antioxidative balance - PAB (P < 0.001) and liver PAB (P < 0.01) and thiobarbituric acid reactive substances - thiobarbituric acid-reactive substances (P < 0.05). Feeding the CR diet increased calcium (P < 0.001) and potassium (P < 0.05) and decreased cadmium (P ≥ 0.05) content in the liver when compared to the C group. Administration of the CR and IN diets increased selenium (Se) and sodium concentrations, whereas decreased zinc content both in the liver (P < 0.01; P < 0.05 and P < 0.05, respectively) and in the kidney (P < 0.01; P < 0.001 and P < 0.001, respectively) of pigs. Additionally, a higher concentration of lead (P < 0.05) was observed in the kidney of pigs fed the CR diet. In conclusion, both dietary supplements had a potential to significantly improve the Se status and oxidoreductive homeostasis in growing pigs.