2.

Haematoxyline and Eosin (H&E) and cleaved caspase-3 staining of tissues of the DMH mouse experiment: (A) Untreated and (B) TQ alone-treated mice showed normal colon mucosa. In the DMH-treated group adenomas with high-grade intraepithelial neoplasia (C) and poorly differentiated carcinoma (E), partly of signet cell ring type (E, magnification), were observed. Mice given DMH+TQ developed adenomas with low-grade intraepithelial neoplasia (D) and demonstrated well differentiated carcinomas of early tumor stage (F). (G and H) Immunohistochemical detection of cleaved caspase-3 disclosed few positive cells and apoptotic bodies in the carcinoma of untreated animals (group 1), whereas tumors of TQ-treated animals (group 3) had considerably higher proportion of cleaved caspase-3 expressing cells (Zeiss Axioscope 50, camera:Nikon Coolpix 990; x100, x200, x400).