Influência da manutenção do tecido esplênico na sobrevida e nos linfócitos TCD4 e TCD8 de ratos submetidos à peritonite fecal

Abstract

Introduction: Asplenic animals are more susceptible to severe infections such as fulminant sepsis and peritonitis, whose mortality rates remain significantly high. Aims: Comparing the survival time of rats subjected to different spleen procedure types, after fecal peritonitis. Investigating whether there were changes in CD4 and CD8 T lymphocyte count, before and after spleen procedures. Correlating the survival of animals subjected to different spleen procedures, followed by peritonitis induction, based on CD4 and CD8 T lymphocytes. Method: thirty young male Wistar rats were distributed into three groups comprising 10 animals each: group MB (n=10) - animals were subjected to spleen manipulation; group ET (n=10) - animals were subjected to total splenectomy; group ESTPI (n=10) - animals were subjected to subtotal splenectomy preserving the lower pole. All animals were subjected to blood collection at two different times - before surgery (T1) and 70 days after surgery (T2) – in order to count CD4/CD8 T lymphocytes based on flow cytometry. Seven days later, each animal was injected with its own feces in order to induce fecal peritonitis; their survival time was recorded from the injection time until animals’ time of death. Survival rate was calculated and compared between groups. Non-parametric Kruskal-Wallis test and Kaplan Meier survival analysis were used to compare survival time (in hours) between groups. Wilcoxon test was used to calculate the number of CD4 and CD8 T lymphocytes before and after surgical procedures. Spearman's coefficient was calculated to correlate the percentage of lymphocytes to animals’ life span. P-value lower than 5% was considered significant. Results: Group 3 (subtotal splenectomy) recorded the longest median lifespan, whereas group 2 (total splenectomy) recorded the shortest one; there was significant difference in lifespan among the three groups (p = 0.013). The percentage of CD4 lymphocytes before and after the surgical procedure did not significantly change in any of the three groups (p > 0.05). However, the percentage of CD8 lymphocytes presented significant decrease in the spleen manipulation and TSPLP groups (p = 0.017), after the surgical procedure (p = 0.022). There was not significant correlation between the percentage of CD4 and CD8 lymphocytes and animal survival rates in all groups (p > 0.05). Conclusions: The survival time of rats subjected to different spleen procedure types, and who were not treated for fecal peritonitis, recorded significant difference among the three groups; Group 2 recorded the shortest survival time. There was decreased number of CD8 T lymphocytes in animals subjected to spleen manipulation and TSPLP. The CD4 and CD8 T lymphocyte count was not correlated to the survival of animals subjected to the different spleen procedures investigated in the current study.