Autotransplantation of Splenic Tissue after Splenectomy in Rats Offers Partial Protection against Intravenous Pneumococcal Challenge

Abstract

Thirty-six splenectomized Sprague-Dawley rats with omental implants of splenic tissue were challenged with intravenous pneumococci. The mortality rate in this group was compared to 31 similarly challenged splenectomized and 28 normosplenic rats. The results showed that while rats with implanted splenic tissue had a better survival rate (p = 0.04) than splenectomized rats, their survival was poorer than that of rats with normal spleens (p = 0.02) (Fischer’s exact test).

Differences between the Histology of Normal Spleen and That of Regenerated Ectopically Implanted Splenic Tissue

“…The number of such lymphocytes present in splenotic tissue should therefore be an im portant determinant of its efficiency, espe cially in dealing with a fast replicating organ ism such as the pneumococcus. Although studies of immunoglobulin responses follow ing splenosis have yielded varied results [3,5,6,12,16,20,24,29], autotransplanted splenic tissue has a limited capacity to deal with bacterial infections [19,28], The re duced amount of white pulp in splenotic tis sue observed in the present investigation provides a morphological basis for this func tional deficiency.…”

“…This theory has been tested experimentally in laboratory animals using autotransplanted splenic tissue after splenectomy as an animal model of splenosis. While results have varied [8,11,18,26,31,33,36], recent work indicates that splenotic tissue offers significant but incomplete protection against bacterial challenge to the splenecto mized rat [19,28], The reason, or reasons, why splenotic tis sue is less efficient than the normal spleen in dealing with bacterial challenge remain un clear. Previous workers have implicated the site of implanation [36], the relatively small mass of splenotic tissue when compared with the normal spleen [7,9,27], its blood flow [7,27], but not its microscopic structure.…”