Fig. 1. Ultrastructural analysis of the integrity of the blood-testis barrier (BTB) following treatment of rats with CdCl₂ (3 mg/kg b.w. via i.p.). (A,B) Electron micrographs of (A) the BTB between two adjacent Sertoli cells at the seminiferous epithelium of a control rat, as an example of a tight junction (TJ), which appears as electron dense material (arrowhead). Magnification, x67,500; (B) a rat testis 24 hours after CdCl₂ treatment illustrating that the TJ were disrupted (arrowheads). Magnification, x45,000. LD, lipid droplet; SC, Sertoli cell; BM, basement membrane; C, collagen network; MC, myoid cell layer.