Critical mass of splenic autotransplant needed for the development of phagocytic activity in rats

Abstract

SummaryWhen total splenectomy is inevitable, heterotopic splenic autotransplantation seems to be the only alternative to maintain the functions of the spleen. The present study was carried out to analyse the critical mass of splenic autotransplant (SAT) for the development of phagocytic activity in rats. Wistar rats were submitted to total splenectomy (TS) alone or in combination with slices of SAT ranging from an average rate of 21·9% (one slice) to 100% (five slices) of the total splenic mass implanted into the greater omentum. Sixteen weeks after the beginning of the experiment, the animals were inoculated intravenously with a suspension of Escherichia coli labelled with Tc-99m. After 20 min, the rats were killed and the liver, lung and spleen or SAT, as well as blood samples were removed to determine the percentage of labelled bacteria uptake in these tissues. As the percentage of the total splenic mass contained in the SAT increased, the bacteria remaining in the blood decreased. From the implant of 26% up to the implant of the total splenic mass (100%) there was no difference in the bacteria remaining in the blood between the healthy animals of the control group and those submitted to TS combined with SAT. This finding shows that the critical mass needed for the development of phagocytic activity of macrophages in splenic autotransplants in adult rats is 26% of the total splenic mass.

Blood clearance of Howell–Jolly bodies in an experimental autogenic splenic implant model

“…Experimental studies investigating the immunoprotective effect of ASIs have been based mostly on exposing animals to various bacterial species, then assessing the level of clearance of these microorganisms from the bloodstream, and death from bacterial sepsis. Blood filtering and the potential benefits of immunization combined with ASI have also been investigated, especially after exposure to pneumococci; this combination increased the rate of bacterial clearance and decreased mortality from sepsis.…”

“…Subsequently, a similar experimental model, with thin splenic slices sutured to the greater omentum and intercalated omental tissue, was used to allow better vascularization. In this model the critical mass needed to achieve efficacious phagocytic activity in macrophages in adult rats occurred when 26·0 per cent of the total splenic mass had regenerated.…”

“…At this time point, a more structured morphological regeneration was also seen. This indicates that, besides a requirement for a critical minimal mass of splenic tissue to be implanted, a critical level of regenerated splenic tissue may be needed for restoration of splenic function.…”

“…In addition, the critical mass of ASI needed for the recovery of phagocytic activity in young adult rats was studied. If 26–100 per cent of the total splenic mass was regenerated, there was no difference in the bacterial index in the blood of rats undergoing total splenectomy combined with ASI compared with that in sham‐operated animals.…”

Preliminary study of coconut water for graft tissues preservation in transplantation

“…The four splenic fragments were sutured side by side on the greater omentum, with 4-0 nylon 5 . All procedures were performed under sterile conditions 6 . Both ovaries were fixed with 4-0 nylon stitches in the right pelvic fat 7 .…”