Influence of the ileum and colon on liver regeneration. Comparative study
Liver; Regeneration; Ileum; Colectomy; Hepatectomy; Rats
Abstract
AIM
The aim of this study was to investigate and compare the effects of ileum and colon resection on liver regeneration.
METHODS
Wistar rats (Rattus norvegicus) weighing 261 ± 34g were randomly allocated to four groups of six animals each. In group I (sham), only laparotomy was performed; in group II, 70% hepatectomy; in group III 70% hepatectomy + ileal resection; and in group IV, 70% hepatectomy + partial colectomy. On the sixth postoperative day, blood was collected by cardiac puncture, followed by euthanasia. Serum dosages of aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, alkaline phosphatase (AF), hepatocyte growth factor (HGF) and transforming growth factor-alpha (TGF-α) were measured. The hepatic regeneration rate was estimated by liver weight per 100 g of body weight at euthanasia/preoperative projected liver weight per 100 g of body weight × 100. The liver samples were submitted to the Ki-67 immunohistochemical reaction.
RESULTS
ALT, AST and AF levels were significantly higher in group III rats when compared to group I, III and IV (p<0.001). In group IV, the levels were significantly lower than in groups II and III (p<0.001). Albuminemia showed significantly lower levels in group III rats when compared to groups I, II and IV. (p<0.001). There was no difference in albuminemia between groups I (sham) and IV (70% hepatectomy + colectomy) rats (p>0.05). HGF and TGF-α levels in group IV rats were significantly higher than in groups I, II and III (p<0.001). Group IV animals exhibited a higher liver regeneration rate than in groups II and III, but the difference was not significant (p>0.05). The liver cell expression of Ki-67 was significantly higher in the remnant liver of group IV rats than in group III (p=0.002). There was no difference in Ki-67 expression between group II and IV rats (p>0.05).
CONCLUSION
Ileum and colon resection have different effects on liver regeneration. Colon resection positively influences liver regeneration, while ileum resection has a negative influence on the regenerative process, in a rat model.