Lectin histochemistry of ethylnitrosourea-induced oligodendrogliomas in the rat.

Oligodendrogliomas (n = 26) induced by ethylnitrosourea (ENU) in wistar rats were examined to assess the lectin specificity to oligodendroglial membranes. Two different types of oligodendrogliomas were found in our material: an isomorphous type (n = 12), and a polymorphous type (n = 14). The first one, with two variants according to its size, macro- (n = 9) and microtumors (n = 3), had predominantly a honey-comb pattern with 'clear halos' around the nuclei without anaplasia. The second type, composed mostly by macrotumours, was anaplastic, with high cellular density, necrosis and intratumoral hemorrhages. Peanut agglutinin (PNA) labelled plasma membranes of well-differentiated cellular components of the first group. The tumoral oligodendrocytes lost the property to bind PNA in the second group of tumours, while Concanavalin A (Con A) showed affinity to intracytoplasmic structures of these tumours. PNA is a reliable marker of oligodendroglial plasma membrane of well-differentiated ENU-induced oligodendrogliomas. This experimental model, using PNA and Con A, may have important clinical applications regarding the biological behaviour of this type of neoplasm.