Evaluation of wistar rat model with pre-transplant subcutaneous transposition of spleen (sts) for possible role in improving results of orthotopic liver transplantation

Orthotopic liver transplantation (OLT) in the rat model remains the animal model of choice for liver transplantation due to the availability of inbred strains, technically simple procedure and the lack of need for immunosuppression. A major limiting factor in the rat liver transplantation is the short anhepatic phase which is poorly tolerated due to ischemia reperfusion injury. Portosystemic shunt induced by subcutaneous transposition of spleen (STS) may help in preventing reperfusion injury. To study this hypothesis 8 rats were subjected to STS which was followed 3 weeks later by portal pedicle clamping for 60 min in 4 rats (STS-60) and 90 min in 4 rats (STS-90). The control group consisted of 8 rats undergoing sham laparotomy by left subcostal incision followed by portal pedicle clamping 3 weeks later for 60 min- 4 rats (SHAM-60) and for 90 min in 4 rats (SHAM-90). These groups were compared on the basis of survival, SGOT levels, intestinal congestion during clamping, collateral formation in the subcutaneous pouch and the histopathological examination of the liver. The ability of the shunt to prevent ischemia reperfusion injury was shown by the survival rate of 100% in STS-60 and STS-90 groups while sham operated groups SHAM-60 and SHAM-90 had survival rates of 25% and 0%, respectively. Intestinal congestion was noted during clamping in the sham operated group but was absent in the STS group. SGOT levels which rose in the first post portal clamping day returned to baseline levels by day 7 in the STS group. Histopathological examination of the livers in STS rats showed maintenance of hepatocellular architecture, absence of sinusoidal dilatation and absence of polymorphonuclear infiltrate. Subcutaneous transposition of spleen can therefore provide an effective portosystemic shunt which is easy to perform. It prolongs the anhepatic phase of rat liver transplantation and can be used to study various factors and mediators involved in ischemia reperfusion injury.

Keywords
Liver transplantation, Rat, Subcutaneous transposition of spleen, Ischemia reperfusion injury.