Kinectics of the pulmonary phase of Schistosoma mansoni in mice treated with dexamethasone

Abstract

In the experimental schistosomiasis mansoni glucocorticoids cause a reduction in the worm burden when administered in the week of infection or, the longest, at the next week. In order to determinate the probable(s) site(s) of reduction of the worm burden, mice were infected with cercariae of LE strain of S. mansoni and dexamethasone was administered daily (50 mg/kg, subcutaneously) starting 1 hour before infection until the eighth day. Mice were sacrificed daily starting on the third day after infection until the ninth day, and schistosomula from lungs were collected. Six weeks after infection, the remaining mice were sacrificed and perfused for adult worm recovery. Analysis of the results showed that the non-treated mice presented larger numbers of lung larvae than the treated ones, and this difference was also found later in the worm burden in the portal system. This difference may reflect the early death of larvae in treated animals, before or after reaching the lungs.

Immunological and parasitological parameters after treatment with dexamethasone in murine Schistosoma mansoni

“…We have reported that the pharmacological effects of DDB include inhibition of NF-KB activation and of TNFβ (Salama et al 2004). Previous studies of the effects of corticoids on murine schistosomiasis showed variable effects that depended on the type of corticoid administered, the dose and the schedule of treatment (Harrison & Doenhoff 1983, Morrison et al 1986, Hermeto et al 1990). It was proposed that the decrease in worm burden that occurred following corticoid treatment was due to impairment of the initial phase of parasite penetration into host tissues (Hermeto et al 1994).…”