Increased liver regeneration rate and decreased liver function after synchronous liver and colon resection in rats.
BACKGROUND
The surgical strategy for the treatment of colorectal cancer and synchronous liver metastases remains controversial. The aim of the present study was to investigate the effects of colonic resection on liver function and regeneration in a rat model.


METHODS
Ninety-six Sprague-Dawley rats were block-randomized into six groups: Group I had a laparotomy performed. Group II had 1 cm colon resected and anastomosed. Group III and V had 40% or 70% of the liver resected, respectively. Additionally Group IV and VI had 1 cm colon resected and anastomosed, respectively. Body weight was recorded on postoperative day 0, 3, 5 and 7. Rats were sacrificed on postoperative day 7 by rapid collection of blood from the inferior vena cava, and endotoxin levels were measured. Remnant liver function was evaluated by means of branched amino acids to tyrosine ratio. Liver regeneration was calculated by (liver weight per 100 g of the body weight at sacrifice/preoperative projected liver weight per 100 g of the body weight) x 100.


RESULTS
The total number of complications was significantly higher in Group VI than Group I, III, IV, and V. Body weight and branched amino acids to tyrosine ratio were both significantly lower in rats that had simultaneous colonic and liver resection performed. Hepatic regeneration rate was significantly higher in the simultaneous colectomy group. Systemic endotoxin levels were unaffected by simultaneous colectomy on postoperative day 7.


CONCLUSIONS
In our model morbidity seems to be related to the extent of hepatic resection. In rats undergoing liver resection, simultaneous colectomy induced a higher degree of hepatic regeneration rate. Body weight changes and branched amino acids to tyrosine ratio were negatively affected by simultaneous colectomy.
Sasanuma
Hideki
H
Department of Surgery, Jichi Medical University, 3311-1, Shimotsuke, Tochigi 329-0498, Japan.
Mortensen
Frank Viborg
FV
Department of Surgical Gastroenterology L, Aarhus University Hospital, Aarhus DK-8000, Denmark.
Knudsen
Anders Riegels
AR
Department of Surgical Gastroenterology L, Aarhus University Hospital, Aarhus DK-8000, Denmark.
Funch-Jensen
Peter
P
Department of Surgical Gastroenterology L, Aarhus University Hospital, Aarhus DK-8000, Denmark.
Okada
Masaki
M
Department of Surgery, Jichi Medical University, 3311-1, Shimotsuke, Tochigi 329-0498, Japan.
Nagai
Hideo
H
Department of Surgery, Jichi Medical University, 3311-1, Shimotsuke, Tochigi 329-0498, Japan.
Yasuda
Yoshikazu
Y
Department of Surgery, Jichi Medical University, 3311-1, Shimotsuke, Tochigi 329-0498, Japan.