Objective: To study the histopathological effect of hepatic arterial infusion of lipiodol on transplanted hepatoma in rats.
Methods: Fourty-one rats bearing Walker-256 transplanted hepatoma were randomly divided into embolization group (n = 35, divided in 5 subgroups, with 7 rats in each) and control group (n = 6). Lipiodol (0.5 ml/kg)emulsified with 0.2 - 0.3 ml of 76% urografin (v:v = 1:1) was infused via gastroduodenal artery into hepatic artery in embolization group. Rats in the control group were given via the same route urografin only. Histopathological changes of the treated tumors were examined by light and transmission electron microscopy.
Results: In the control rats treated with urografin alone, the average tumor size increased 2.8 fold on day 3, while that in the lipiodol treated rats increased 1.7 fold (P < 0.01). Compared with the control group, on day 3, 5, 10 after embolization treatment, tumor necrosis was more extensive (P < 0.01). In one of the treated rats, the tumor was completely necrotic on day 10. Inflammatory reaction was marked in the early post-embolic period, but it was replaced by fibrous tissue encapsulation. From day 1 on, in 17 of the 18 treated rats, apoptotic cells, identified by typical morphology under light and electronic microscopes, were observed, mainly in the tumor periphery.
Conclusion: In addition to cellular necrosis, apoptosis may be another important mechanism leading to cell death in hepatoma treated with transarterial embolization.