Effects of lipopolysaccharide (LPS) administration on apoptosis in the brook trout ovary. Sections of paraffin-embedded ovaries from saline (A)- and LPS (B)-injected brook trout were analyzed for in situ end-labeling by TUNEL. Two representative images of ovaries from saline- and LPS-injected trout are shown. In C, hematoxylin-eosin stained sections of representative ovaries from saline (left) and LPS-injected (right) brook trout are shown. Prior to fixation, the ovaries were de-yolked by gentle pressure. F, follicular cells; C, chorion.