| Radiofrequency (RF) is one of the new technology which can destroyed the local tumor tissue with less damage to the intervening tissue. RF has been used to treat liver cancer in some hospitals recently. Some studies suggested that hyperthermia can increase the immune function of tumor-bearing animal. RF is one of the most common hyperthermia therapy. The effect of RF therapy on immune function of tumor-bearing body needs to be researched urgently in order to use more rationally and develop this technology. We established the model of mice bearing liver cancer for RF therapy. In this study, light and electron microscopy, MTT, double-colour flow cytometry, enzyme linked immune sorbent assay and RT-PCR were used to explore pathological changes of tumor tissue after RF therapy, the splenocyte proliferation , splenocyte cytotoxicity and spleen Thl/Th2 cytokine expression pattern in the BALB/C mice bearing H22 liver cancer. The main results and conclusions are as follows:1. H22 liver cancer cell has stable biology characteristics, and the incidence of cancer was 100%. The BALB/C mice bearing H22 liver cancer were treated by RF with different therapentic temperature. The cure rates in 70℃ group, 65℃ group and 60℃group were 100% 100% 66. 7% respectively, mortality rates were56. 7%, 46. 7%, 40. 0% respectively, and recurrence rate were 0% 0% 33. 3% respectively.Recurrence rates and cure rates were no significantly different between 70℃ group and 65℃ group, but significantly higher and lower in 60℃ group (P<0.05) , respectively. Histology examination immediately after RF treatment showed that target cells shrank, nucleus fragmentated, and nucleus condensed. Electron microscopy examination showed that nucleus fragmentated and cells dissolved with organelles disappearing and plasma membrane rupturing. We suggest that RF therapy is effective and feasible for liver cancer in mice. We recommended that the therapy dose is 70℃ or 65℃ for five minutes, and 65℃ for five minutes is the best because of higher cure rate and lower morality rate.2. Splenocyte proliferation was determined using MTT in mice bearing H22 liver cancer . The A570 values in two weeks after bearing tumor group is lower than that in before therapy group (P<0.05) , and the A570 values in three weeks after bearing tumor group is also lower than that in before therapy and normal groups (P<0.05). It were no significantly different before and after surgery resection (P>0.05) . The A570 value in two weeks and three weeks after RF therapy groups were higher than that in before therapy and normal groups (P<0.05) . Remarkably, the A570 value in one week, two weeks and three weeks after RF therapy groups were higher than that in one week, two weeks and three weeks after surgery resection groups, respectively (P,0.05). Splenocyte cytotoxicity was detected by double-colour flow cytometry. When effective cells /targeted cells ratio was 30:1, the death rates was higher than that when effective cells /targeted cells ratio was 15:1. With the same effective cells /targeted cells ratio, the death rate of targeted cells in three weeks after bearing tumor group was lower than that in normal and before therapy group (P<0.05) ; It were no significantly different before and after surgery resection (P>0.05) ; the death rate of targeted cells in one week and two weeks after RF therapy groups were higher than that in one week and two weeks after surgery resection groups,respectively(P<0.05), and than that in normal and before therapy groups(P<0.05). We suggest that the H22 liver cancer cells solidified by RF may have the same antigen as H22 liver cancer cells. The solidified cells could stimulate splenocyte activation and proliferation, and increase splenocyte cytotoxicity.3. We detected the expression pattern of T helper type 1 (Thl) and T helper type 2(Th2) cytokine in splenocyte culture supernatants. We also studied the levels of cytokine mRNA expression in splenocyte cells. The results were as follows: IL-2 and IFN- r concentration in two weeks a...
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