Trypanosoma cruzi : serum levels of nitric oxide and expression of inducible nitric oxide synthase in myocardium and spleen of dogs in the acute stage of infection with metacyclic or blood trypomastigotes.

Abstract

The par tic i pa tion of nitric oxide (NO) in the con trol of blood par a si te mia and par a sit ism dur ing the acute phase of infec tion in dogs inoc u lated with blood try pom astig otes ( BT) or meta cy clic try pom astig otes (MT group) of Bere nice -78 Try pan o soma cru zi strain has been eval u ated. Ani mals of the MT group (n = 4) pre sented increased lev els of serum NO through out the infec tion when com pared with the BT ( n = 4) or con trol (n = 4) groups, and a delay in par a si te mia peak com pared with the BT group. In spleen frag ments, tis sue par a sit ism was not observed but the MT group pre sented larger areas asso ci ated with induc ible NO syn thase (iNOS) in rela tion to BT and con trol groups. Heart frag ments of MT-infected ani mals exhib ited com par a tively low tis sue par a sit ism and high iNOS expres sion, while ani mals of the BT group pre sented high inflam ma tory infil trate, high tis sue par a sit ism and low iNOS expres sion. These results indi cate that the source of inoc u lum can inter- fere with the devel op ment of the acute phase of Cha gas dis ease, and may also trig ger a dis tinct par a site–host inter ac tion dur ing this phase.