Increased liver regeneration rate and decreased liver function after synchronous liver and colon resection in rats

Effect of the Ileum and Colon on Liver Regeneration

PURPOSE

The colon and ileum play significant roles on liver physiology. Studies about simultaneous hepatectomy and colectomy or enterectomy are scarce and controversial. We investigated and compared the effects of ileum and colon resection on liver regeneration.

MATERIALS AND METHODS

Twenty four Wistar rats were allocated in group I-(sham), group II-70% hepatectomy; group III-70% hepatectomy + ileal resection, and group IV-70% hepatectomy + partial colectomy. On the sixth day, serum hepatic enzymes, albumin, hepatocyte growth-factor (HGF) and transforming growth factor-alpha (TGF-α) were measured. The hepatic regeneration rate was estimated. Ki-67 immunohistochemical analysis was done in remnant liver.

RESULTS

Hepatic enzymes levels were significantly higher in group III rats comparing to the other groups (p < 0.001). In group IV, the levels were significantly lower than in groups II and III (p < 0.001). Albuminemia was significantly lower in group III rats comparing with the other groups (p < 0.001). Albuminemia was not different comparing groups I and IV (p > 0.05). Cytokines HGF and TGF-α levels in group IV were significantly higher than in the other groups (p < 0.001). Liver regeneration rate was higher group IV than in groups II and III, and the difference was statistically significant (p = 0.002). The hepatocytes expression of Ki-67 was significantly higher in the remnant liver of group IV than in group III (p = 0.002). There was no difference in Ki-67 expression between groups II and IV (p > 0.05).

CONCLUSION

Ileum and colon resection have different effects on liver regeneration. Colon resection positively influences liver regeneration, while ileum resection negatively influences the regenerative process, in a rat model.

Influence of the colon in liver regeneration of rats submitted to hepatectomy and colectomy

OBJECTIVE

to evaluate whether colectomy, associated with 70% hepatectomy, influences liver regeneration in rats.

METHODS

we distributed 18 Wistar rats in three groups of six animals each. In group I (sham), we performed laparotomy; In group II, colectomy + 70% hepatectomy; In group III, only 70% hepatectomy. On the 6th postoperative day, we collected blood by cardiac puncture under anesthesia, followed by euthanasia. We performed serum dosages of aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin and alkaline phosphatase (AF), hepatocyte growth factor (HGF) and transforming growth factor-α (TGF-α). We calculated liver regeneration by the formula: liver weight ratio per 100g body weight at the time of euthanasia / liver weight preoperatively projected for 100g body weight × 100.

RESULTS

ALT and AST levels were significantly lower in group II when compared with group III (p<0.001). Albuminemia showed significantly higher levels in group II. Levels of HGF and TGF-α in group II were significantly higher than in group III. The percentage of hepatic regeneration was significantly higher in group II than in group III.

CONCLUSION

Colectomy performed simultaneously with 70% hepatectomy had a positive influence on liver regeneration in rats. Further research is needed to reveal the molecular mechanisms of this effect and to characterize the colon influence in liver physiology.

A preliminary in vivo study of the effects of OPN on rat liver regeneration induced by partial hepatectomy

Osteopontin (OPN) is a member of Th1 cytokine secreted by activated lymphocytes and macrophages. However, it deserves to be studied whether OPN could promote cell activation or proliferation, and then facilitate hepatic self-repair during liver regeneration (LR). This study is designed to further reveal the effects of OPN on LR in vivo. Firstly, quantitative reverse transcription-PCR (qRT-PCR) and western blot (WB) were utilized to validate the expression profile of endogenous OPN in rat regenerating livers after partial hepatectomy (PH). Then OPN expression vector, two shRNA expression vectors and their respective test vectors were successfully constructed. Afterwards, test vectors were administrated into mouse livers via tail vein to find the more efficient shRNA. Furthermore, OPN expression vector and the more efficient shRNA expression vector were injected into rat regenerating livers, and then the changes in liver regeneration and hepatic microstructure were respectively detected by liver regeneration rate and HE staining, while the expressions of several marker genes were detected by qRT-PCR and WB. Endogenous OPN was strikingly up-regulated in both mRNA and protein level during LR, especially at 12 and 72 h after PH. The shRNA expression vector Opn(313) was found to be more efficient than Opn(887) in silencing the expression of Opn. Then OPN expression vector and Opn(313) were injected into rat remnant livers, and it showed that OPN overexpression aggravated hepatic necrosis and leukocytes infiltration, while OPN silencing inhibited liver regeneration rate and the expressions of PCNA and CCL2, but augmented that of BAX. In conclusion, OPN might enhance inflammation and cell proliferation, attenuate cell apoptosis, and ultimately facilitate liver regeneration at the termination stage of liver regeneration.