| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2001: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2000: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
Pancreas remnant can regenerate after major pancreatectomy in rats. Gut hormones secreted in response to pancreatic exocrine insufficiency are considered involved deeply in the mechanism. On the other hand, pancreatic disorders induced by duct obstruction and pancreatitis induce expression of reg protein and various growth factors that activate regenerative process of the pancreas. However, little is known about the interactive effects of these intestinal and pancreatic factors on pancreas regeneration
This study investigated the role of these factors in rats using surgical models as follows. 65%Px or 65%Lig : Pancreas was tied off at ventral of the portal vein and the distal pancreas (splenic and gastric lobes) was resected (pancreatectomy abbreviated as Px) or left in the place (ligature abbreviated as Lig), respectively. 65%Sham : The pancreas was prepared but not tied. 80%Px or 80%Lig : In addition to 65%Px or Lig, duodenal lobe was tied off at a just anal level of common bite pancr
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eatic duct junction with duodenum and the distal pancreas (lower half of duodenal lobe) was resected (Px) or left in the place (Lig), respectively. 80%Sham : The pancreas was prepared but the ligatures were not placed
Each group was fed either with normal powder diet or the diet supplemented with pancreatin (1/30 w/w), respectively. On postoperative day (POD) 8 and 21 (in 80% groups alone), rats were sacrificed and the pancreas was removed, weighed and histologically analyzed. The regeneration percent of the pancreas remnant was calculated on the basis of the mean value of body weight-normalized weight of the corresponding part in sham-operated groups. The percent of the pancreas remnant was 36.4 ± 1.4% in 65%Sham and 19.6 ± 0.7% in 80%Sham, respectively. Values are mean ± SE.Statistical significance was accepted when p<0.05
On POD 8, wet weight of pancreas remnant was significantly increased in Px and Lig groups both in 65% and 80% experiments. Regeneration percent of Px/Lig/Sham in normal diet was 29 ± 7/14 ± 10/4 ± 6 in 65% and 24 ± 4/35 ± 13/5 ± 5% in 80%, respectively. Diet had no significant effect. On POD 21, pancreas weight was significantly increased only in Px group. Regeneration percent of Px/Lig/Sham in normal diet was 54 ± 8/11 ± 8/-13 ± 4%. Again, diet had no significant effect. The tissue was analyzed by insulin immuno-staining and in situ hybridization for PDX-1. No remarkable difference was noted in the pancreas remnant in both analysis. However, in the duct-ligated lobe of Lig group, diffuse expression of PDX-1 and a few insulin-positive cells were observed in the duct epithelium, suggesting activation of regeneration process
In conclusion, this study failed to show significant effect of pancreatic enzyme supplemented in the diet, suggesting that intestinal factor may not play a major role in pancreas regeneration. Clear difference in the results between POD 8 and POD 21 is very interesting. Further investigation of the cause of this difference seems to lead to profound understanding of the mechanism of pancreas regeneration Less
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