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

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).

Influence of selenium treatment on the acute toxicity of dibutyltin dichloride in rats.

BACKGROUND/AIMS: Dibutyltin dichloride (DBTC) is an organotin compound used as a model for acute pancreatitis. The aim was to determine the effect of various doses of Na-selenite on the pathogenesis and course of DBTC-induced toxic changes in organs and serum of rats. METHODS: Experimental pancreatitis was induced by intravenous administration of 6 mg kg(-1) BW DBTC. Na-selenite was applied as a single intravenous dose of 5 mg kg(-1) BW and as daily oral dose of 1 mg kg(-1) BW. Malondialdehyde (MDA) was detected to observe the level of oxidative stress. The tin concentration in bile and urine shows the elimination of DBTC. Organ changes were indicated by serum parameters as well as histology. RESULTS: DBTC causes an acute pancreatitis, cholestasis and liver lesions determined by specific elevated serum parameters and several histological lesions. Na-selenite significantly diminished MDA concentration, lipase, bilirubin and transaminases as well as organ injuries compared to only DBTC-treated rats. CONCLUSIONS: The 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. The generation of DBTC-Na-selenite complexes could also be a mechanism to decrease the toxicity of organotin compounds like DBTC.

Repeated administration of a mild acute toxic dose of di-n-butyltin dichloride at intervals of 3 weeks induces severe lesions in pancreas and liver of rats.

Di-n-butyltin dichloride (DBTC) induced thymus atrophy, bile duct lesions, pancreatitis, and liver lesions in rats. Depending on dose [6 and 8 mg/kg intravenous (i.v.) DBTC] and time (1-24 weeks), the lesions in pancreas developed to a pancreatic fibrosis and the lesions in liver to liver cirrhosis. A single i.v. administration of 4 mg/kg DBTC induces a mild interstitial pancreatitis after 2-4 days followed by a restitutio ad integrum after 21-28 days. In the present study, the lesions of biliopancreatic duct, pancreas, and liver of rats after repeated administration of 4 mg/kg DBTC i.v. at intervals of 3 weeks have been investigated. The histopathological changes of pancreas and liver were examined by light microscopy 1,4, and 7 days and 2,3,4,6,9, and 12 weeks after administration of DBTC. Furthermore, pathobiochemical parameters of pancreatitis (amylase and lipase activity in serum), liver lesions (alkaline phosphatase activity and bilirubin in serum), and of fibrosis (hyaluronic acid in serum) were studied. Repeated administration of rats with DBTC (4 mg/kg i.v.) at intervals of 3 weeks induced an acute interstitial pancreatitis and after 9-12 weeks, a pancreatic fibrosis and liver lesions (intrahepatic bile duct hyperplasia, inflammation in periportal tract, and necrosis). In serum, elevated levels of alkaline phosphatase, bilirubin, and hyaluronic acid were found. This study demonstrates that the organotin compound induces toxic effects on pancreas and liver of rats by repeated administration of lower doses at long intervals. The risk of exposure to organotin at long intervals should be considered.

Influence of curcumin on cyclosporin-induced reduction of biliary bilirubin and cholesterol excretion and on biliary excretion of cyclosporin and its metabolites.

We investigated the ability of curcumin, which can be extracted from different Curcuma species, to prevent cyclosporin-induced reduction of biliary bilirubin and cholesterol excretion, and its influence on biliary excretion of cyclosporin (CS) and its metabolites in the bile fistula model in rats. I.v. injection of curcumin (25 and 50 mg/kg) after 30 min increased dose-dependently basal bile flow (30 microliters/kg/min) up to 200%, biliary bilirubin excretion (3000 pmol/kg/min) up to 150%, and biliary cholesterol excretion (22 nmol/kg/min) up to 113%. CS (30 mg/kg) reduced bile flow to 66% and biliary excretion of bilirubin and of cholesterol to 33% of the basal value 30 min after i.v. injection. I.v. administration of curcumin (25 and 50 mg/kg) 30 min after CS increased bile flow dose dependently again to 130% for 1 hour and biliary excretion of cholesterol and of bilirubin to 100% of the basal value for 30 and 150 min, respectively. Injection of curcumin 15 min before CS prevented the CS-induced drop of bile flow at 50 mg/kg and reduction of biliary bilirubin excretion already at 25 mg/kg until the end of the experiment (180 min). The CS-induced reduction of biliary cholesterol excretion, however, was not prevented by curcumin. Finally, the biliary excretions of CS (1200 ng/kg/min) and its metabolites (1200 ng/kg/min) were slightly reduced by curcumin at a dose of 50 mg/kg (to 83% of the initial values). The clinical importance of these controversial effects remains to be shown.

Antidotal effects of 2,3-dimercaptopropane-1-sulfonic acid (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) on the organotoxicity of dibutyltin dichloride (DBTC) in rats.

1. Dialkyltin compounds have been widely used in industry and agriculture, mainly as biocides, catalysts and plast stabilizer. In dependence on the length of the alkyl chains these organotins exert toxic effects on the immune system, the bile duct, liver and pancreas. It has been supposed that similar to organoarsenic the toxicity of the dialkyltin compounds is related to reactions with biological dithiol groups. Therefore, in the present study, the antidotal effects of 2,3-dimercapto-propane-1-sulfonic acid (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) on the organotoxic effects of dibutyltin dichloride (DBTC, single administration of 27 micromol kg(-1) b.w. i.v.) in rats were studied using different doses (100 and 500 micromol kg(-1) b.w.) and routes of administration (i.p. and p.o.) of both chelators. Several parameters of organotoxicity (thymus weight and cellularity, bile duct diameter, histological lesions of pancreas and liver, activities of amylase, lipase and alkaline phosphatase, bilirubin and hyaluronic acid in serum) were measured from 6 h to 8 weeks. 2. DMPS and DMSA diminished the DBTC induced bile duct, pancreas and liver lesions stronger than the thymus atrophy. Moreover, the development of a fibrosis of the pancreas and a cirrhosis of liver several weeks after single administration of DBTC to rats was inhibited by DMPS and DMSA. The antidotal effects on serum parameter were observed after both administration routes of the chelators. DMPS was more effective than DMSA in most measured parameters. The decrease in the biliary excretion of organotin by DMPS and DMSA seems to be the reason for the pronounced protective effects of DMPS and DMSA on bile duct, pancreas and liver. 3. For the treatment of poisonings with dibutyltin compounds, the administration of DMPS or DMSA can be recommended.

The course of pancreatic fibrosis induced by dibutyltin dichloride (DBTC).

In summary, in addition to an acute interstitial pancreatitis the organotin compound DBTC induced a pancreatic fibrosis in rats. The course of the pancreatic fibrosis was studied 2-36 weeks after single i.v. treatment of rats with 6 or 8 mg/kg DBTC. The pancreatic fibrosis induced by DBTC differs from other experimental models of acute pancreatitis. Extensive infiltration by mononuclear cells is present in fibrotic areas without pancreatic atrophy or lipomatosis. The presence of chronic inflammatory lesions characterized by the destruction of exocrine parenchyma and fibrosis and in the later stages the endocrine parenchyma, indicate a chronic pancreatitis. In completion of the experimental model of the DBTC-induced acute interstitial pancreatitis in rats, the described late fibrotic effects on rat pancreas may be used as an experimental model of chronic pancreatitis.

The influence of ethanol on long-term effects of dibutyltin dichloride (DBTC) in pancreas and liver of rats.

The present study was done to determine the additional influence of daily ethanol intake (15% in drinking water ad libitum) on long-term toxic effects of a single administration of dibutyltin dichloride (DBTC, 8 mg/kg b.w. i.v.) in pancreas and liver of rats. Pathohistological changes in pancreas, bile duct and liver as well as pathobiochemical parameters of pancreatitis (amylase and lipase activity), liver lesions (alkaline phosphatase activity and bilirubin) and fibrosis (hydroxyproline and hyaluronic acid) were measured 1 day and 1 to 24 weeks after DBTC- and DBTC/ethanol administration. DBTC alone induced in rats an acute interstitial pancreatitis as well as acute bile duct and liver lesions in the early experimental phase. Later on, the acute inflammatory processes in pancreas and liver took a chronic course resulting in pancreatic fibrosis and liver cirrhosis. Ethanol increased the toxic effects of DBTC on pancreas and liver during the acute and chronic course. In the acute phase lasting 1 day to 2 weeks, ethanol enhanced the DBTC toxicity on acinar cell and bilio-pancreatic duct epithelium as well as the formation of obstructive ductal plugs by necrotic cell debris. The obstruction and cholestasis in the DBTC/ethanol-group were significantly stronger as in the DBTC-group. The significant increase of hydroxyproline in urine and hyaluronic acid in serum of the DBTC/ethanol treated rats after 12 to 24 weeks was connected with a more severe chronic inflammatory fibrosis in pancreas and liver in comparison to the DBTC-treated group.

Acute interstitial pancreatitis in rats induced by dibutyltin dichloride (DBTC): pathogenesis and natural course of lesions.

Dibutyltin dichloride (DBTC; 6 mg/kg body weight, i.v.) induced acute interstitial pancreatitis in rats. The course of the pancreatitis was examined within 28 days by light and electron microscopy as well as by pathobiochemistry (amylase, lipase, alkaline phosphatase, and bilirubin in serum; tin concentration in biliopancreatic juice, tissue, and concretions). The pathogenesis of the DBTC-induced pancreatitis in rats was studied by different experimental designs (in intact animals, after bile duct ligation, after surgical bypass of the bile duct). DBTC caused toxic necrosis of the biliopancreatic duct epithelium, which is then shed into the duct and forms obstructing plugs in the distal common bile duct. Interstitial pancreatitis occurred during the first 4 days, accompanied by significantly increased activities of serum alpha-amylase and lipase. After 7 days extensive infiltration of the pancreatic interstitium with mononuclear cells was observed. Twenty-eight days after administration of DBTC one-third of the rats showed periductal and interstitial fibrosis as well as an active inflammatory process in the pancreas. The findings suggest a twofold pathogenesis of the DBTC-induced pancreatitis: first, the cytotoxic effects on the biliopancreatic duct epithelium lead to epithelial necrosis with obstruction of the duct, subsequent cholestasis, and interstitial pancreatitis; and second, the hematogenic DBTC effects cause direct injury of pancreatic cells (mitochondrial damage, autophagy, cell necrosis) followed by interstitial edema and inflammation. Both processes lead to this special type of DBTC-induced acute pancreatitis with a tendency to a chronic course, when the obstruction of the duct and cholestasis persist.

[The effect of barbiturates and diphenylhydantoin on the mitotic activity of thymocytes and bone marrow cells in mice and rats]. / Uber die Wirkungen von Barbituraten und Diphenylhydantoin auf die mitotische Aktivität von Thymozyten und Knochenmarkszellen von Mäusen und Ratten.

Phenobarbitone (PB) and diphenylhydantoin (DPH) inhibited the mitotic rate of thymocytes and bone marrow cells (colchicine blocked metaphases) dose- and time-dependent (20-80 mg/kg i.p., 12-48 hours) in mice and rats in vivo. The inhibition of proliferation was evident also after repeated administration of the drugs and other barbiturates. Other substances with a depressive effect on the central nervous system (etomidate, ketamine, chlorpromazine and ethanol) did not influence the mitotic rate of the thymocytes. Inhibition of the mitotic rate by PB was also observed in adrenalectomised rats. In vitro PB and DPH inhibited the mitotic rate of thymocytes in therapeutic and toxicologically relevant concentrations (10(-5)-10(-3) mol/l). The investigations indicate a direct effect of PB and DPH on rats. Possible immunosuppressive effects are discussed.

Acute pancreatitis and bile duct lesions in rat induced by dibutyltin dichloride.

After i.v. or i.p. administration of a single dose of dibutyltin dichloride (DBTC) the following changes were observed in pancreas and bile ducts of male rats: acute interstitial pancreatitis, enlargement of diameter and destruction of epithelial cells of the bile ducts, increase of serum alkaline phosphatase activity. The effects were dependent on the dose of DBTC (1, 4 or 6 mg/kg body weight), the route of administration and the time after treatment. The pancreatitis induced by DBTC is under further investigation as a model of experimental pancreatitis.

[Seasonal variations of the mitotic activity of thymocytes in CBA mice]. / Jahreszeitlichen Schwankungen der mitotischen Aktivität von Thymozyten bei CBA-Mäusen.

Considerable seasonal variations were exhibited by mitotic activities of thymocytes in CBA mice. In April and May they were about twice as high as in October and November. Biorhythmic changes in mitotic activity of thymocytes should be taken into consideration for any study of drug effects on the thymus.

[Biological testing of biomaterials in the framework of permitted procedures. 2]. / Zur biologischen Prüfung von Biomaterialien im Rahmen des Zulassungsverfahrens. 2. Mitteilung.

Submitted is the revised version of a proposal for a guideline for biological testing of materials (biomaterials) which remain temporarily or permanently, resp., at or in the human body or have contact with drugs or body fluids outside the human body.

[Effects of dithiocarbamates on the mitotic activity of thymocytes]. / Wirkungen von Dithiocarbamaten auf die mitotische Aktivität von Thymozyten.

The effects of dithiocarbamates on the mitotic activity of thymocytes were studied in vitro and in vivo. The mitotic activity was determined by counting of the metaphases blocked by colchicine. Using thymocytes of mice the mitotic activity in short-time cultures was inhibited (50%) by the following concentrations of the substances under study (EC50-values in mol/l): tetraethylthiuramdisulfide; (1; disulfiram) 4.2.10(-9); diethyldithiocarbamate (2) 3.2.10(-8), Cu-2, 2.6.10(-8), Zn-dimethyldithiocarbamate (3; Ziram) 1.9.10(-8), Zn-ethylene-bis-dithiocarbamate (4; Zineb) 2.3.10(-6). Using rat and guinea-pig thymocytes the ED50- values for 1 and 2 were found in the same concentration range as compared with thymocytes of mice. There was no impact on the vitality of cells by the mitosis inhibiting concentrations. In vivo the mitotic activity of thymocytes in mice was decreased only after application of high doses (500 mg/kg i.p.) of 2. After depletion of reduced glutathione (GSH) by the pretreatment of mice with diethylmaleate the effects of 2 were increased in vivo. In vitro GSH (10(-4) mol/l) decreased the mitosis inhibiting activity of 2 in mice thymocytes and the inhibition of the SH-enzyme ecto-ATPase in rat thymocytes. It is supposed that the inhibition of mitosis is due to the reaction of dithiocarbamates with SH-groups of microtubules and other functionally important proteines. The formation of tiyl radicals from dithiocarbamates may play a certain role in redox processes which can be influenced by GSH.

[The exclusion of nonspecific effects in testing potential anti-inflammatory agents following intraperitoneal administration]. / Zum Ausschluss unspezifischer Effekte bei der Testung potentieller Antiphlogistica nachintraperitonealer Gabe.

The intraperitoneal (i.p.) administration of potential antiphologistics of the group of DL-2-phenylglycinalkylester hydrochlorids caused beside the inhibition of the carrageenan rat paw oedema a high increase of the glucocorticoid-induced tyrosin transaminase activity (TTA) in the liver. Using this group of compounds the exclusion of unspecific antiphlogistic effects as a consequence of peritoneal irritation and glucocorticoid liberation was studied. For comparison phenylbutazone, hydrochlorid acid and carrageenan were examined after i.p. administration. The results showed that in contrast to hydrochlorid acid and carrageenan the antiphlogistic effects of DL-2-phenylglycinalkylester hydrochlorids were not elicited by unspecific irritation. Therefore the i.p. administration can be used in testing antiinflammatory drugs, if indirect effects have been excluded in adrenalectomized animals. The determination of the TTA-activity of the liver as an indicator of glucocorticoid liberation is not sufficient for exclusion of unspecific effects in testing antiphlogistics after i.p. administration.

Effects of diethyl maleate on non-protein sulfhydryl content and cellular functions of mouse thymocytes in vitro.

The electrophilic compound diethyl maleate (DEM, 10(-5)-10(-3) M) decreased the content of non-protein sulfhydryl groups in mouse thymocytes in vitro and affected mitotic activity, spontaneous migration and viability of the cells. The mitotic activity of mouse thymocytes was most sensitive to DEM. It is probable that the decrease of the cell content of reduced glutathione (GSH) led to a failure of GSH-dependent cellular functions, such as mitosis and migration. Cytosolic supernatants of mouse and rat thymocytes exhibited GSH S-transferase activities on DEM and 1-chloro-2,4-dinitrobenzene as electrophilic substrates.