Tan Bing, Huang Jie-Fei, Wei Qun, Zhang Hong, Ni Run-Zhou
Department of Digestive Medicine, Affiliated Hospital of Nantong Medical College, Nantong 226001, Jiangsu Province, China.
World J Gastroenterol. 2005 Oct 14;11(38):5938-43. doi: 10.3748/wjg.v11.i38.5938.
To study the anti-hepatoma efficiency of arsenic trioxide (As(2)O(3)) in the treatment of experimental rat hepatocellular carcinoma (HCC) induced by 2-acetamidofluorene (2-FAA) and to elucidate the possible mechanisms.
SD rats (2 mo old) had been fed with 2-FAA for 8 wk to induce HCC, and then they were treated with As(2)O(3) or matrine. On d 29, the rats were killed and the liver was weighed and liver tumors were counted. The histological changes of liver tissue were observed under microscope, and the cellular dynamic parameters were studied by flow cytometry. Immunohistochemistry (two-step method) was used to observe the expression of vascular endothelial growth factor (VEGF) and micro-vessel density (MVD) on consecutive sections. The pathological parameters were also analyzed, the levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBi), and direct bilirubin (DBi).
The number of liver tumors decreased significantly in groups treated with As(2)O(3), especially in medium-dose (1 mg/kg) group (t = 2.80, P<0.01). As(2)O(3) caused HCC cell death via apoptosis; necrosis was seen and apoptosis was common when the dose was 1 mg/kg. Proliferation index decreased sharply in medium-dose (1 mg/kg) group (7.87+/-4.11 vs 24.46+/-6.49, t = 2087, P<0.01), but not in 0.2 mg/kg group. However, S-phase fraction decreased dramatically in both groups, it reached the bottom level only when the dose was 1 mg/kg compared with control (0.40+/-0.13 vs 3.01+/-0.51, t = 2.97, P<0.01), and it was obviously accompanied with accumulation of cells in G(0)/G(1) (G(0)/G(1) restriction). The expressions of VEGF and MVD in medium-dose (1 mg/kg) group were significantly lower than normal saline group (0.63+/-0.74 vs 2.44+/-0.88, P<0.05; 15.75+/-3.99 vs 47.44+/-13.41, t = 2.80, P<0.01). Compared with normal saline group, medium- and low-dose groups As(2)O(3) and matrine lowered the levels of ALT in serum (61.46+/-9.46, 63.75+/-20.40, 61.18+/-13.00 vs 108.98+/-29.86, t = 2.14, P<0.05), but had no effect on the level of serum AST, TBi, and DBi.
As(2)O(3) had inhibitory effect on growth of experimental HCC in rats induced by 2-FAA, but had no obvious effect on normal hepatic cells. The mechanisms may involve decrease of cell division, accumulation of cells in G(0)/G(1) phase, apoptosis of tumor cells, and inhibitory effect on angiogenesis through blocking VEGF.
研究三氧化二砷（As₂O₃）对2-乙酰氨基芴（2-FAA）诱导的实验性大鼠肝细胞癌（HCC）的抗肝癌作用，并阐明其可能的机制。
2月龄SD大鼠喂饲2-FAA 8周以诱导HCC，然后分别用As₂O₃或苦参碱治疗。第29天处死大鼠，称取肝脏重量并计数肝肿瘤。在显微镜下观察肝组织的组织学变化，并用流式细胞术研究细胞动力学参数。采用免疫组织化学（两步法）观察连续切片上血管内皮生长因子（VEGF）的表达及微血管密度（MVD）。同时分析病理参数、血清天冬氨酸氨基转移酶（AST）、丙氨酸氨基转移酶（ALT）、总胆红素（TBi）和直接胆红素（DBi）水平。
As₂O₃治疗组肝肿瘤数量显著减少，尤其是中剂量（1mg/kg）组（t = 2.80，P<0.01）。As₂O₃通过诱导凋亡导致HCC细胞死亡；当剂量为1mg/kg时可见坏死且凋亡常见。中剂量（1mg/kg）组增殖指数急剧下降（7.87±4.11比24.46±6.49，t = 2087，P<0.01），而0.2mg/kg组无明显变化。然而，两组S期细胞比例均显著下降，仅当剂量为1mg/kg时降至最低水平，与对照组相比（0.40±0.13比3.01±0.51，t = 2.97，P<0.01），且明显伴有细胞在G₀/G₁期的蓄积（G₀/G₁期阻滞）。中剂量（1mg/kg）组VEGF表达及MVD均显著低于生理盐水组（0.63±0.74比2.44±0.88，P<0.05；15.75±3.99比47.44±13.41，t = 2.80，P<0.01）。与生理盐水组相比，中、低剂量As₂O₃组及苦参碱组血清ALT水平降低（61.46±9.46、63.75±20.40、61.18±13.00比108.98±29.86，t = 2.14，P<0.05），但对血清AST、TBi和DBi水平无明显影响。
As₂O₃对2-FAA诱导的实验性大鼠HCC生长有抑制作用，但对正常肝细胞无明显影响。其机制可能包括细胞分裂减少、细胞在G₀/G₁期蓄积、肿瘤细胞凋亡以及通过阻断VEGF抑制血管生成。
