Fig. 3. Immunohistochemical localization of ZO-1 in the seminiferous epithelium of adult rat testes during CdCl₂-induced BTB damage. (A) Low magnification of a cross section of a rat testis at 0 hours immunostained with an anti-ZO-1 antibody, and (B) a control section where normal rabbit serum was substituted for the primary antibody. (C-H) Micrographs at high magnifications of rat testes after CdCl₂ treatment (3 mg/kg b.w.i.p.). Immunoreactive ZO-1 appears as reddish-brown precipitates localized at the basal compartment consistent with the site of the BTB (see arrowheads in A). These micrographs are typical of the results from at least 120 cross sections from three testes of different rats. Scale bar: (A,B) 200 µm; (C-H) 80 µm; (C inset, applies to insets in D-G) 20 µm.