Trypanosoma cruzi infection and/or administration of the nonsteroidal anti-inflammatory nimesulide increase the number of colonic crypts overexpressing metallothioneins in rat colon carcinogenesis
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Data
2006
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Resumo
Trypanosoma cruzi infection and nonsteroidal anti-inflammatory drugs
inhibit colorectal carcinogenesis by mechanisms not completely known
and metallothionein proteins (MTs) may be involved in this process.
Sixty-six male Wistar rats weighing 90 to 120 g were randomly
divided into seven groups (GI to GVII). GI, GII and GIII animals were
subcutaneously infected with 200,000 trypomastigote forms of the Y
strain of T. cruzi. After 8 weeks, GI, GII, GIV, and GVI were injected
with one weekly subcutaneous dose of 12 mg/kg dimethylhydrazine
for 4 weeks. In sequence, GI, GIV and GV were treated with nimesulide
(10 mg/kg per dose, five times per week for 8 weeks). Groups I, III, IV,
and VI had 12 animals, and each of the other groups had 6 animals. All
the animals were euthanized 8 weeks after the last dimethylhydrazine
injection. The colons were fixed and processed for MT immunohisto-
chemistry. The index of MT-overexpressing colonic crypts (MTEC)
was estimated as the percentage of MT-stained crypts in relation to the
total number of crypts scored. Five hundred crypts per animal were
scored. Data were analyzed by the Kruskal-Wallis test followed by the
Dunn test. There was an increase in MTEC index in the groups either
infected with T. cruzi or treated with nimesulide or both infected and
treated when compared to control (401, 809, and 1011%, respective-
ly). We suggest that the increased formation of MTEC may be related
to the protection against carcinogenesis provided both by T. cruzi
infection and nimesulide.
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Trypanosoma cruzi, Dimethylhydrazine, Metallothioneins, Colon carcinogenesis, Nimesulide
Citação
ESCALANTE, R. D. et al. Trypanosoma cruzi infection and/or administration of the nonsteroidal anti-inflammatory nimesulide increase the number of colonic crypts overexpressing metallothioneins in rat colon carcinogenesis. Brazilian Journal of Medical and Biological Research, RibeirĂŁo Preto, v. 39, n. 7, p. 895-899, 2006.