Expression of osteopontin in the pericystic layer of hepatic hydatid cyst

Objective To investigate the expression and distribution of osteopontin (OPN) in the pericystic layer of Echinococcos granulsus cyst. Methods 60 surgically excised cysts were studied with HE and immunohistochemistry staining by using antibodies specific for OPN. Immunofluorescence double labeling technique and Media Cybernetics Image (Pro Plus 5.1 software) were used to appraise the relationship between the OPN and macrophages (CD68).Results Expression of OPN was found at various degree in hydatid cysts, 75% (45/60) was distributed in the intra-layer at the parasite side, 8.3% (5/60) distributed in the extra-layer near the side of liver parenchyma ("exocyst"-layer vs "adventitia"-layer, P0.01). Macrophages were identified between the intra-layer and extra-layer, and OPN was observed in most of the macrophages. Meanwhile, OPN was concurrently found with the deposit of calcium in a similar distribution in the hydatid cyst. Conclusion Osteopontin mainly distributes in the intra-pericystic layer of hepatic hydatid cyst.