Microbiological and inflammatory effects of murine recombinant interleukin-10 in two models of polymicrobial peritonitis in rats

A protective effect of interleukin-10 (IL-10) against the development of le thal shock has been demonstrated in various animal models. In contrast, the immunosuppressant properties of this mediator have been minimally evaluate d in low-mortality models of infections. The clinical, microbiological, and inflammatory effects of murine recombinant IL-10 (mrIL-10) therapy were ev aluated in two models of peritonitis in rats, which differed in the degree of severity of peritoneal inflammation 3 days after inoculation of Escheric hia coli and Bacteroides fragilis with or without Enterococcus faecalis. Th e severity of the disease remained unchanged compared to that in control an imals. A dose-related decrease in the peritoneal phagocyte count was observ ed in the treated groups compared to the counts in control animals. The sub sequent experiments were performed exclusively in the mixed gram-positive-g ram negative model, which exhibits an intense and prolonged inflammatory re sponse with similar criteria. The early effects of mrIL-10 (evaluated 6 h a fter inoculation), repeated injections of mrIL-10 (four doses injected from 0 to 9 h after bacterial challenge), and pretreatment (two doses injected 6 and 3 h before inoculation) were evaluated. The clinical and microbiologi cal parameters remained unchanged in the treated animals. Decreases in the peritoneal phagocyte count and the peritoneal concentration of tumor necros is factor were observed following repeated injections of mrIL-10. In summar y, our data suggest that mrIL-10 does not worsen the manifestations of seps is. However, these results need to be confirmed in clinical practice.