Osteopontin expression is associated with hepatopathologic changes in Schistosoma japonicum infected mice

To investigate osteopontin expression and its association with hepatopathologic changes in BALB/C mice infected with Schistosoma japonicum.

The schistosomal hepatopathologic mouse model was established by abdominal infection with schistosomal cercaria. Liver samples were obtained from mice sacrificed at 6, 8, 10, 14, and 18 wk after infection. Liver histopathological changes were observed with hematoxylin-eosin and Masson trichrome staining. The expression of osteopontin was determined with immunohistochemistry, reverse transcription-polymerase chain reaction, and Western blotting. The expression of α-smooth muscle actin (α-SMA) and transforming growth factor-β1 (TGF-β1) were determined by immunohistochemistry. Correlations of osteopontin expression with other variables (α-SMA, TGF-β1, hepatopathologic features including granuloma formation and degree of liver fibrosis) were analyzed.

Typical schistosomal hepatopathologic changes were induced in the animals. Dynamic changes in the expression of osteopontin were observed at week 6. The expression increased, peaked at week 10 (P < 0.01), and then gradually decreased. Positive correlations between osteopontin expression and α-SMA (r = 0.720, P < 0.01), TGF-β1 (r = 0.905, P < 0.01), granuloma formation (r = 0.875, P < 0.01), and degree of liver fibrosis (r = 0.858, P < 0.01) were also observed.

Osteopontin may play an important role in schistosomal hepatopathology and may promote granuloma formation and liver fibrosis through an unexplored mechanism.