Fig. 2.

Silibinin feeding inhibits neoplastic progression of prostate in TRAMP mice at various stages. In the experiment detailed in Fig.1, at the time of necropsy dorsolateral prostate glands were harvested and histopathologically analyzed for the different stages of the neoplastic progression. (A) Effect of silibinin feeding on the incidence and pattern of PIN lesions in the 4-12 week group of TRAMP mice. (B) Effect of silibinin on the incidence of PIN/adenocarcinoma of prostate in the 12-20, 20-30 and 30-45 week groups of TRAMP mice. Fisher’s Exact test was used to compare incidence of PIN and adenocarcinoma in positive control versus silibinin-fed groups. P values <0.05 were considered significant. *, P<0.001; $, P<0.05. (C) Silibinin feeding reduces the severity of prostatic lesions (tumor grade) of TRAMP prostate in a stage specific manner. Different stages of prostate tissues were graded as described in “Results”. The maximum histological score for the prostate lobe was used to calculate a mean for the treatment group. Data is presented as mean peak histological score and ± SEM (error bars) of each group. The difference between the positive controls versus the respective silibinin-fed group was analyzed by unpaired two-tailed Student’s t-test. P values <0.05 were considered significant. *, P<0.001. (D) The photomicrographs (×10 magnification) representative of the mean peak histological score of a treatment group show the H&E staining of the TRAMP prostate at different stages. Control, positive control (TRAMP mice); Sb, silibinin; PIN, prostate intraepithelial neoplasia; LG, low grade PIN; HG, high grade PIN; WD, well differentiated adenocarcinoma; MD, moderately differentiated adenocarcinoma; PD, poorly differentiated adenocarcinoma.