Figure 4.

Histochemical and immunohistochemical analyses of HA and CSPG in human placentas of different gestational stages. The gestational stages of the placentas are indicated in the left margin. HA: Untreated (a, e, i, and m) and S. hyalurolyticus hyaluronidase-treated (b, f, j, and n) placental tissue sections were histostained with HABP. Only the tissue stroma was intensely stained with HABP, and staining was not observed either in the intervillous space or on the syncytiotrophoblast surface in placentas of all gestational stages (a, e, i, and m). In all cases, no staining was observed after treatment with S. hyalurolyticus hyaluronidase (b, f, j, and n). CSPG: The placental tissue sections were treated with chondroitinase ABC to remove GAG chains and then immunostained using either rabbit polyclonal antibodies against the core proteins of the placental low-sulfated CSPG (c, g, k, and o) or preimmune serum from the rabbit used for raising antibodies against the placental CSPG (d, h, l, and p). The anti-CSPG antibodies stained fibrous, filamentous materials in the intervillous space and the fibrous projections of the syncytiotrophoblast lining. Preimmune serum-treated tissue sections showed no staining. All tissue sections were photographed under light microscopy. Ivs, intervillous space; Syn, syncytiotrophoblasts; Fbv, fetal blood vessels; St, stromal tissue; RBC, red blood cells. Original magnifications, ×100.