Effect of Tocilizumab on Acinetobacter baumannii Lung Infection in an Immunosuppressed Rat Model

Abstract

Our study aimed to investigate effect of tocilizumab on the lung tissue in the presence of Acinetobacter baumannii infection in immunosuppressed rats. A forty-eight female Wistar albino rats were divided equally into eight groups: Group 1: Healthy (H), Group 2: Immunosuppressed (IM), Group 3: Healthy rats given A. baumannii bacteria (H+BAC), Group 4: Immunosuppressed rats given A. baumannii bacteria (IM+BAC), Group 5: Healthy rats given tocilizumab (H+TCZ), Group 6: Immunosuppressed rats given tocilizumab (IM+TCZ), Group 7: Healthy rats given A. baumannii bacteria and tocilizumab (H+BAC+TCZ), Group 8: Immunosuppressed rats given tocilizumab and A. baumannii bacteria (IM+BAC+TCZ). Fourteen days after the immunosuppression of group 2, 4, 6 and 8 with hydrocortisone, group 3, 4, 7 and 8 were A. baumannii was dropped into the trachea. One hour after A. baumannii application, TCZ was administered to Groups 5, 6, 7 and 8. NF-κB, IL-6 and NLRP3 mRNA expressions were decreased in the IM group compared to the healthy group (P<0.05). Although NF-κB, IL-6 and NLRP3 mRNA expression decreased in the IM+TCZ group compared to the healthy group (P<0.05) NF-κB, IL-6 and NLRP3 mRNA expression increased in the H+TCZ group (P<0.05). Despite decreasing cytokines, A. baumannii has been shown to increase infection-related lung injury. This suggests that in patients currently or recently using steroids, tocilizumab may increase organ damage due to opportunistic infection.