Course and regression of acute interstitial pancreatitis induced in rats by repeated serial subcutaneous cholecystokinin-octapeptide injections

Simultaneous proteosome inhibition and heat shock protein induction by bortezomib is beneficial in experimental pancreatitis

The proteosome inhibitor bortezomib is used in the treatment of patients with multiple myeloma. Proteosomes are responsible for the degradation of I-kappaB, the inhibitory protein of transcription factor nuclear factor kappa B (Nf-kappaB). The heat shock protein (HSP) inducing effect of bortezomib is also documented. The aim of our work was to test the anti-inflammatory effect of bortezomib in cholecystokinin-octapeptide (CCK-8)-induced acute pancreatitis. Male Wistar rats were divided into three groups (n=8 in each). Group P received an i.p. injection of physiological saline (p.s.) 60 min. before the induction of acute pancreatitis by three hourly s.c. injections of 100 microg/kg CCK-8. Group BP received 1 mg/kg bortezomib dissolved in p.s. 1 h previous to pancreatitis induction. Group C was treated with the vehicle (p.s.). Animals were exsanguinated 4 h after the last injection of CCK-8. Bortezomib pre-treatment significantly reduced the pancreatic weight/body weight ratio, and improved the histology by decreasing the extent of vacuolization and infiltration. Bortezomib pre-treatment inhibited I-kappaBbeta degradation, and induced the synthesis of HSP72. The results confirmed the anti-inflammatory effect of bortezomib in acute experimental pancreatitis. This effect of the drug is presumably mediated by the inhibition of Nf-kappaB activation and induction of HSP synthesis.

Acute taurodeoxycholate-induced pancreatitis in the rat is associated with hyperCCKemia

BACKGROUND

Cholecystokinin (CCK) has been suggested to be involved in the development and course of acute pancreatitis. In the present study we measured plasma CCK concentrations in acute experimental pancreatitis (AEP) in the rat, and evaluated the role of circulating CCK levels on the initial pancreatic damage in pancreatitis.

METHODS

Endogenous hyperCCKemia was induced by surgical biliodigestive shunt (BDS) and exogenous hyperCCKemia by infusion of CCK-8S. The CCK-A receptor antagonist devazepide was used to antagonize the effect of CCK. Pancreatitis was induced by pancreatic duct infusion of sodium taurodeoxycholate 4 wk after the BDS operation or 1 wk after the start of the infusions. Nonpancreatitic sham- and BDS-operated rats, respectively, were used as control animals as were groups of otherwise untreated rats with pancreatitis. The animals were sacrificed 6 h after induction of pancreatitis. Concentrations of CCK were determined in plasma as were protein and amylase levels in the pancreas and peritoneal exudates. The extent of pancreatic necroses was assessed microscopically.

RESULTS

Pancreatitis caused an 11-20-fold increase of circulating CCK as measured after 6 h. In pancreatitic rats with induced hyperCCKemia, there was a further marked increase of plasma CCK. Pancreatic weight and edema, protein and amylase contents, and extent of necroses were the same regardless of the level of plasma CCK. Devazepide had no influence on the studied pancreatic parameters.

CONCLUSION

We conclude that acute taurodeoxycholate-induced pancreatitis in the rat is associated with elevated plasma CCK concentrations. There seems, however, not to be any correlation between the degree of hyperCCKemia and the extent of initial pancreatic damage.

Spontaneous and cholecystokinin-octapeptide-promoted regeneration of the pancreas following L-arginine-induced pancreatitis in rat

CONCLUSION

In L-arginine (Arg)-induced pancreatitis, evidence of acute inflammation was observed on d 1-3. Continuous tissue atrophy became visible at the sites of previous pancreatic necrosis, with simultaneous regeneration of the pancreas, mainly around the Langerhans islets. Administration of low doses of cholecystokinin-octapeptide (CCK-8) increased the inflammatory signs of pancreatitis in the early phase, but subsequently diminished the level of atrophy and accelerated the processes of regeneration in this model of pancreatitis.

BACKGROUND

The aim of this work was to study the regenerative processes following Arg-induced pancreatitis in rats. Besides the spontaneous regeneration, the effects of low doses of CCK-8 on the laboratory and morphologic parameters in this type of experimental pancreatitis were investigated.

METHODS

Male Wistar rats were divided into three groups. In group I, the rats received 200 mg/100 g body weight of Arg i.p. twice, at an interval of 1 h, and 0.5 mL saline was administered s.c. twice daily. In group II, besides the same amount of Arg, the rats received 1 microgram/kg of CCK-8 s.c. in 0.5-mL saline twice daily (7 AM and 7 PM). In the control animals (group III), an identical amount of glycine was administered i.p. instead of Arg at the same times. The rats were examined on d 1, 3, 7, 14, and 28 after pancreatitis induction. The pancreatic weight/body weight ratio (pw/bw) was calculated in each case. The serum levels of amylase, and glucose and the pancreatic contents of soluble protein, trypsin, amylase and DNA were determined, and histologic examinations were performed.

RESULTS

In groups I and II, both pw/bw (3.5 +/- 0.2 mg/g and 4.1 +/- 0.28 mg/g, respectively) and the serum amylase level (8900 +/- 560 IU/L and 11100 +/- 1390 IU/L, respectively) were significantly elevated on d 1 vs group III (2.1 +/- 0.06 mg/g and 5562 +/- 373 IU/L, respectively). Pw/bw was significantly decreased in groups I (0.96 +/- 0.12 mg/g, 0.8 +/- 0.1 mg/g, and 1.8 +/- 0.1 mg/g, respectively) and II (1.4 +/- 0.15 mg/g, 1.7 +/- 0.2 mg/g, and 1.95 +/- 0.1 mg/g, respectively) on d 7, 14, and 28 vs group III (2.6 +/- 0.3 mg/g, 3.1 +/- 0.15 mg/g, and 2.7 +/- 0.1 mg/g, respectively), whereas in group II it was significantly elevated vs. group I on d 7 and 14. The pancreatic contents of soluble protein, DNA, trypsin and amylase were significantly decreased on d 3-14 in groups I and II vs group III. The pancreatic DNA level was significantly elevated in group II (1.23 +/- 0.2 mg/pancreas) vs group I (0.7 +/- 0.1 mg/pancreas) on d 7. In group II, the soluble protein (73.1 +/- 15.5 mg/pancreas) and amylase (1104 +/- 160 IU/pancreas) levels were significantly elevated on d 14 as was that of trypsin (27.2 +/- 3.1 IU/pancreas) on d 28, vs group I (26.4 +/- 5.3 mg/p, 525 +/- 111 IU/pancreas, and 16.3 +/- 1.1 IU/pancreas, respectively). On histologic sections, the signs of acute inflammation of the pancreas were more pronounced in group II than in group I on d 1-3. After that time, in spite of the progressive atrophy of the pancreas, the signs of tissue repair were more expressed in group II.