ACTION OF DIAZEPAM® FRONT TO EXPERIMENTAL INFECTION WITH Leptospira interrogans SOROVAR POMONA IN HAMSTER (Mesocricetus auratus)

Abstract

Benzodiazepines, diazepam specifically, are the most indicated drugs from psychotropics, and there are evidences of its immunosuppressor effects. This study was aimed to evaluate the immunosuppression action of this drug in leptospiral infection in hamster. Four groups of 10 animals were used: G1, treated with 1 mL of Fletcher media and sacrificed after 86 hours; G2, inoculated with 1 mL Leptospira interrogans serovar Pomona suspension in Fletcher media, with 10⁶ microorganisms; G3, inoculated as G2 and treated with 1.5 mg.Kg^-1 of diazepam at the time of the inoculation, and G4, inoculated as G2 and treated before the inoculation with the same doses of diazepam during 5 days. For the isolation and quantification of leptospires from kidneys, the cultures were assayed in Fletcher media, in 10^-1, 10^-2, 10^-3 and 1:4, 1:16 e 1:64 dilutions, respectively, in antibiotic saline solution (ASS). The animals from G2, G3 and G4 had been sick and dead until 86 hours post-inoculation (p.i.). For the quantification of leptospires in animals from G2, its isolation was identified until 26th day, but nine animals (90%) were positives in 1:64 dilution, and the others in 1:16 dilution. In G3 and G4 the isolation of leptospires was observed since 18th day p.i., but these results had been kept until 24 and 23 days in G3 and G4, respectively. The recovery of leptospires in G2 was possible in 80% animals only since the 26th day p.i., while in G3 and G4 it was observed in 40% and 20%, 24 and 23 days p.i., respectively. These results show lower leptospiral concentration in groups treated with diazepam, and higher “in vitro” incubation period. No difference in G3 and G4, based on the incubation period was observed. However, diazepam influenced the immune response of hamsters infected with L. interrogans serovar Pomona, with low bacterial recover in kidneys, suggesting other mechanisms involved in the immune response not affected by the benzodiazepines.