Influencia da lesão da area septal do cerebro de ratos sobre os linfocitos T (CD4+ e CD8+) do baço e efeitos sistemicos induzidos pelo tumor Walker 256
AUTOR(ES)
Fernando Guimarães
DATA DE PUBLICAÇÃO
2000
RESUMO
Some studies have shown the influence of limbie-hypothalamie areas on the immune response modulation. Concerning the septal nueleus, the whole lesion of this limbie area impaired the humoral immune response of rats immunized with sheep red blood eells, while lesions of the medial septal nueleus produced a long lasting inhibition of T Iymphoeyt proliferation induced by mitogens. The proposal of the present study was to investigate the influenee of septal area lesion on frequeneies of splenie T CD4+ and T CDS+ Iymphoeytes, during tumor development. Therefor, septal-Iesioned rats (LW), obtained through stereotaxie surgery, were compared with sham-operated rats (SW), afier one subeutaneous (se) inoculation of Walker 256 Ar tumor cells (a cell variant obtained from Walker 256 A tumor, distinguished by presenting a high regression ineidence). The adrenocortical aetivity in the mediation of septal lesion effects was evaluated by assessing serum corticosterone. The influenee of septal lesion on systemie effeets induced by the tumor, like body weight gain and, sodium and water renal retention was also investigated (by using the multifocal se inoeulation model of Walker 256 A cells). It was suggested that ehanges in these parameters would help as an indireet indication of the immunological function alterations. Conceming the systemie effects, sodium and fluid retention induced by the Walker 256 A tumor was temporarily reduced in animais with septal area lesions. This effect was possibly a result of an inhibition of antidiuretie hormone release. By using the Walker 256 Ar tumor cells, it was observed tumor regressions in 46.2 % of the SW group and 57.1 % of the LW group two weeks afier se inoculation. In both groups SW and LW, the frequency of splenic T CD4+ Iymphocytes was significantly reduced in rats which tumors did not regress (SW = 19.5:t 1.4 %; LW = 23.8:t 1.6 %) compared with rats with tumor regression (SW = 29.3:t 2.4 %; LW = 31.4 :t 1.6 %). As a consequence, the CD4+/CD8+ ratio was also significantly reduced in rats without tumor regression (SW = 0.91 :I:: 0.07; LW = 1.20 :t 0.07) in relation to those with tumor regression (SW = 1.45 :I:: 0.1; LW = 1,59 :t 0.1 %). Therefore, septal area lesion did not affect the frequencies of T Iymphocytes. Nevertheless, the alterations observed in the frequencies of T Iymphocytes, as well as in CD4+/CD8+ ratio were associated with tumor development (continuous growth or regression). It was also observed that tumor continuous growth or tumor regression, as well as the immune response associated with these events were not affected by adrenocortical activity
ASSUNTO(S)
ACESSO AO ARTIGO
http://libdigi.unicamp.br/document/?code=vtls000197602Documentos Relacionados
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