methylcellulose and Pneumococcal-Infections

Splenectomy impairs survival after pneumococcal challenge in rats, while preservation of sufficient splenic tissue can be protective. This study investigated the effects of methylcellulose on stimulation of splenic weight, splenic histology, reticuloendothelial (RE) activity, and survival after pneumococcal infection. Methylcellulose increased spleen weight four- to five-fold but did not improve RE function or survival after infection. These parameters correlated best with the weight of the remnant in animals that did not receive methylcellulose. The functional limitations of splenic autotransplants were not corrected by methylcellulose stimulation of splenic weight. Preservation of a splenic remnant with intact blood supply is preferable to autotransplantation of the spleen to conserve RE capability.

Topics: Animals; Female; Liver; Methylcellulose; Mononuclear Phagocyte System; Organ Size; Phagocytes; Pneumococcal Infections; Rats; Rats, Inbred Strains; Spleen; Splenectomy

22 male Sprague-Dawley rats were divided into two groups, of which group I received methylcellulose and group II saline intraperitoneally for 12 weeks. After ligation of the splenic artery of the animals in group I and sham operation of the rats in group II, the injections were continued for a further 9 weeks. At the operation, the group I animals all showed signs of hypersplenism with anemia, and leuko- and thrombocytopenia. The platelet counts normalized after the operation, a marked leukocytosis developed and the anemia was further aggravated. At the end of the study, the animals were challenged with 4 x 10(6) colony-forming units of pneumococci type 1, resulting in deaths of 11 of 12 animals in group I, in contrast to survival of all 10 rats in group II (p = 0.000017).

Topics: Animals; Hypersplenism; Leukocytosis; Ligation; Male; Methylcellulose; Pancytopenia; Pneumococcal Infections; Rats; Rats, Inbred Strains; Splenic Artery

Hypersplenism was induced in rats by intra-peritoneal injections of methylcellulose. These rats developed an outsize spleen and had significantly depressed values for hemoglobin concentration, hematocrit and platelet count. The rats given methylcellulose were also found to be more susceptible to a challenge with a standardized intravenous injection of Streptococcus pneumoniae and had a significantly higher mortality rate than the control rats.

Topics: Animals; Disease Susceptibility; Hematocrit; Hemoglobins; Hypersplenism; Male; Methylcellulose; Mice; Platelet Count; Pneumococcal Infections; Rats; Rats, Inbred Strains