Influence of daily oral prophylactic selenium treatment on the dibutyltin dichloride (DBTC)-induced pancreatitis in rats

Abstract

Dibutyltin dichloride (DBTC) is an organotin compound used as model for acute and chronic pancreatitis. Oxidative stress is one of the mechanisms of propagation of acinar cell injury in acute pancreatitis. Selenium is an essential cofactor in the antioxidant glutathione peroxidase pathway. Selenium levels are described to be subnormal in patients with acute and chronic pancreatitis. The aim of our studies was to determine the prophylactic effect of Na-selenite [5 mg kg^-1 body weight (b.w.) per os (p.o.) 7 days] on the pathogenesis and course of DBTC- induced pancreatitis. Male inbred rats (LEW-1W Charles River) of 150 g body weight were used in this study. Experimental pancreatitis was induced by intravenous administration of 6 mg kg^-1 b.w. DBTC in rats. Na-selenite was administered as daily oral dose of 5 mg kg^-1 b.w. 7 days before induction of DBTC-pancreatitis. Malondialdehyde (MDA) was measured for monitoring levels of oxidative stress. Elimination of DBTC was reflected as tin concentration in bile and urine. Organ changes were indicated by serum parameters as well as histology. A prophylactic Na-selenite application significantly diminished MDA- and bilirubin concentration in serum, activities of lipase and transaminases as well as organ injuries compared to DBTC- treated rats in the absence of Na-selenite. The prophylactic oral treatment with Na-selenite in the scope of DBTC-induced pancreatitis points to a reduced oxidative stress characterized by diminished MDA serum levels and a milder course of pancreatitis suggesting prophylactic substitution with Na-selenite to probably elicit beneficial effect on the clinical outcome in patients with endoscopic retrograde cholangiopancreatography (ERCP).

Keywords: DBTC; acute pancreatitis; oxidative stress; selenium.

Table 1. Concentrations of tin (µg g^-1) in bile, urine, pancreas and liver 4 hours and 7 days after daily administration of Na-selenite (Na-se; 5 mg kg^-1 b.w. p.o.), after single dose of DBTC (6 mg kg^-1 b.w. i.v.) and after daily administration of Na-selenite (5 mg kg^-1 b.w. p.o.) + DBTC (6 mg kg^-1 b.w. i.v.). Data indicate mean values ± SD of n = 6 rats in each group, *P < 0.05 for comparison of DBTC vs. corresponding Na-selenite + DBTC group.

Table 2. Concentration of selenium (µg g^-1) in bile, urine, pancreas and liver 4 hours and 7 days after daily administration of Na-selenite (5 mg kg^-1 b.w. p.o.), after single dose of DBTC (6 mg kg^-1 b.w. i.v.) and after daily administration of Na-selenite (5 mg kg^-1 b.w. p.o.) + DBTC (6 mg kg^-1 b.w. i.v.). Data indicate mean values ± SD of n = 6 rats in each group, *P < 0.05 for comparison of DBTC vs. corresponding Na-selenite + DBTC group.

Figure 1. Impact of Na-selenite on DBTC-induced dilatation of the biliopancreatic duct. a) Biliopancreatic duct 7 days after Na-selenite administration. b) Biliopancreatic duct 7 days after DBTC administration. c) Biliopancreatic duct 7 days after Na-selenite + DBTC administration. Arrows indicate the biliopancreatic duct in the respective image.

Figure 2. Influence of Na-selenite on DBTC-induced acute interstitial pancreatitis. Images depict hematoxilin/eosin staining of a normal structure of pancreas in Na-selenite-treated rats (a, magnification x 80) whereas DBTC-induced acute interstitial pancreatitis (b, magnification x 40). In rats treated with combination of DBTC and Na-selenite a mild interstitial pancreatitis can be noticed (c, magnification x 120). Pictures were taken 7 days after administration of the indicated test substances, respectively. Scale bars indicate 100 µm, respectively.

Figure 3. Influence of Na-selenite on DBTC-induced liver malfunction. Images depict hematoxilin/eosin stainings of a normal structure of the liver in Na-selenite-treated rats (a, magnification x 80) whereas DBTC caused inflammation, isolate necrosis and intrahepatic bile duct hyperplasia (b, magnification x 40). In rats treated with combination of DBTC and Na-selenite the DBTC- induced inflammation, necroses and intrahepatic bile duct hyperplasia were reduced (c, magnification 40). Pictures were taken 7 days after administration of the indicated test substances, respectively. Scale bars indicate 100 µm, respectively.

Figure 4. Modulation of serum MDA concentrations by DBTC and Na-selenite. MDA-concentration were measured in serum of rats 1, 2, 4 and 24 hours after administration of Na-selenite, DBTC and Na-selenite + DBTC. Data indicate mean values ± SD of n = 6 rats in each group, *P < 0.05 for comparison of DBTC vs. corresponding Na-selenite + DBTC group.

Figure 5. Modulation of serum lipase by DBTC and Na-selenite. Activity of lipase was quantified in serum of rats 1, 2 and 7 days after administration of Na-selenite, DBTC and Na-selenite + DBTC. Mean values ± SD, n = 6 in each group. Data indicate mean values ± SD of n = 6 rats in each group, *P < 0.05 for comparison of DBTC vs. corresponding Na-selenite + DBTC group.

Figure 6. Modulation of serum alkaline phosphatase and bilirubin by DBTC and Na-selenite. Alkaline phosphatase activity (a) and bilirubin concentrations (b) were determined in serum of rats 2, 7, 14 and 28 days after administration of Na-selenite, DBTC and Na-selenite + DBTC. Data indicate mean values ± SD of n = 6 rats in each group, *P < 0.05 for comparison of DBTC vs. corresponding Na-selenite + DBTC group.

Figure 7. Modulation of serum transaminases by DBTC and Na-selenite. Transaminases (Alanin- Aminotransferase [ALAT] and Aspartat-Aminotransferase [ASAT]) were quantified in serum of rats 2, 7, 14 and 28 days after administration of Na-selenite, DBTC and Na-selenite + DBTC. Data indicate mean values ± SD of n = 6 rats in each group, *P < 0.05 for comparison of DBTC vs. corresponding Na-selenite + DBTC group.