Cadmium induces apoptosis in the pituitary gland of Podarcis sicula

In mammals evidence that cadmium (Cd) induces apoptosis has been demonstrated in several cell-types, such as murine fibroblasts (Biagioli et al., 2001), endothelial cells (Lizard et al., 1999), renal cells (Chen & Huan, 1998) and also in the pituitary gland of rats (Poliandri et al., 2003). Less is known about the cytotoxic effects of this metal at the pituitary level in the reptiles, important bioindicators. In this study we have exposed a group of 15 lizards to an acute treatment by an intraperitoneal injection of a single and massive dose (2mg/Kg-BW) of CdCl2; another group of 15 lizards was used like control. Serial sections of 6 µm of the pituitary gland were processed for routine histological and immunohistochemical staining by ABC technique for caspase 3 and TUNEL technique for detecting apoptotic cells in situ. In the pituitary gland of P. sicula, already after 2 days the apoptotic cells appeared to increase significantly compared with those of the control. After 7 days instead, there was no considerable increment. But after 16 days the increment of apoptotic cells was much raised, above all in Rostral Pars Distalis (RPD), in which various cells showed a strongly immunostained nucleus with irregular shape. Since an increase of the apoptosis was observed above all in the RPD, we can conclude that in the lizard P. sicula Cd is particularly cytotoxic for anterior pituitary cells.