Estudo imunocitoquimico das catepsinas D e B em celulas trofoblasticas gigantes de camundongos

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

The trophoblastic giant cells (TGC) differentiate from trophectoderm sheets or from the ectoplacental cone of mouse embryos and are committed to blastocyst implantation and placentation. It has attributed a high invasive capability and phagocytosis to the TGC which degenerate and remove the maternal tissues. However, the exact mechanism controlling their invasive behavior remains to be solved. Recently it has been proposed that the secretion of proteolytic enzymes to the extra cellular space by tumour cells could be a mechanism of metastasis. This mechanism could be related to TGC invasive activity. In the aim to investigate the participation of lysosomal proteolytic enzymes in such a mechanism of TGC, the presence of cathepsin D and B by immunochemical and immunocytochemical approaches as analyzed. Mice uterine implantation sites and placentas from 8th to 18th days of pregnancy (dop) were processed for cryosections, paraffin embedding, epoxy resin and LR-white resin embedding. Pregnant uterine horn homogenates of same dop were prepared for SDS-P AGE and western-blotting. It was used rabbit polyclonal antibo dy anti-cathepsin D and anti-cathepsin B. In Immunohystochemical, the anti-cathepsins immunoreactive sites were analyzed by immunoperoxidase/DAB and imunofluorescence methods. The protein A-gold method was used for immunoelectronrnicroscopy. The TGCs were found surrounding the whole embryo and placenta making maternal-foetal interface at all developmental stages. At the light microscopy level, the immunoreactions were seen in the cytoplasm of TGC and inside compartments surrounded by cytoplasm processes. Positive reaction was seen near the interface between TGC and maternal tissues. At the ultrastructurallevel, the gold particles were seen to label the small primary and large secondary lysosomes present in the cytoplasm of TGC. The immunolabelings were also seen on the extracellular compartment around the TGC and in the compartments surrounded by cytoplasm processes. In these compartments, cell debris resembling degenerative endometrial cells as well as extracellular matrix elements such as collagen fibrils were found. SDS-P AGE and western-blotting showed a 45 kD and 24 kD bands for cathepsin D and B respectively in the uterine homogenates. These findings confirm the presence of cathepsin D and B in the lysosomeendosome system of TGC. Furthermore, the immunelectronrnicroscopy strong1y suggests that cathepsin D is secreted to the extracellular compartment. This is probably related to the mechanism of invasivity where the proteolytic enzymes are released in to the surrounding tissues facilitating progression of the TGC invasion

ASSUNTO(S)

imunocitoquimica trofoblastico

ACESSO AO ARTIGO

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