复方中药抗氧化剂对局部^(60)Co照射荷瘤大鼠肝氧化损伤的保护作用

Protection of antioxidants compound of Chinese drug on liver oxidative injury by local ^(60)Co irradiation in rats with tumor

目的:研究荷瘤大鼠局部放疗引起的肝脏氧化损伤以及复合抗氧化剂的保护作用. 方法:采用Walker-256肿瘤细胞株接种大鼠皮下,得到实体瘤,摘除实体瘤分割成小块植入大鼠的右后腿皮下,制成大鼠荷瘤模型,将荷瘤大鼠随机分成3组,分别为肿瘤模型组、单纯放疗组和抗氧化剂保护组,同时选取正常大鼠作为阴性对照组.抗氧化剂保护组每日给予复合抗氧化剂灌胃,分次对单纯放疗组和抗氧化剂保护组的荷瘤大鼠进行60Co γ射线局部照射4次,每次间隔1 wk,累计剂量为47Gy,最后一次照射后7 d,处死大鼠,取血清和肝脏分别测定谷胱甘肽硫转移酶(GST)、丙二醛(MDA)、总超氧化物歧化酶(T-SOD)、含锰超氧化物歧化酶(Mn-SOD)、谷胱甘肽(GSH)、总抗氧化力(TAC)、一氧化氮(NO)、一氧化氮合酶(NOS)活性、NOS表达和总蛋白含量. 结果:与阴性组相比,单纯放疗组GST活性和MDA含量显著升高(479±17 vs 427±59,50.3±1.0 vs 46.8±2.3, 33.7±8.8 vs 21.4±7.2,P<0.05,P<0.01,P<0.01), 抗氧化剂保护组GST活性和MDA较单纯放疗组显著降低(421±36 vs 479±17,47.5±1.0 vs 50.3±1.0,21.7±6.8 vs 33.7±8.8,P<0.05,P<0.01,P<0.01).单纯放疗组T-SOD、Mn-SOD活性和GSH含量以及TAC显著低于非照射组(39.3±7.0 vs 48.8±2.8,18.7±6.2 vs 28.8±2.5,0.44±0.13 vs 0.57±0.06,20.7±5.3 vs 26.5±3.3,P<0.01,P<0.01,P<0.01,P<0.05),而抗氧化剂保护组T-SOD、Mn-SOD活性和GSH含量以及TAC显著高于单纯放疗组(47.7±4.3 vs 39.3±7.0,28.2±7.7 vs 18.7±6.2,0.61±0.22 vs 0.44±0.13,26.3±1.7 vs 20.7±5.3,P<0.01,P<0.01,P<0.01,P<0.05).单纯放疗组NO含量和NOS活性显著高于对照组(1.22±0.08 vs 0.98±0.15,4.92±0.94 vs 3.63±0.77,P<0.01, P<0.05),抗氧化剂保护组NO含量和NOS活性及表达显著低于单纯放疗组(0.77±0.22 vs 1.22±0.08,3.62±0.49 vs 4.92±0.94,P<0.01,P<0.05). 结论:荷瘤动物局部照身寸可以引起放疗部位以外的肝脏的氧化损伤,而高效的复合抗氧化剂可以通过提高抗氧化酶活性以及降低NO含量、NOS活性及表达等起到有效的保护作用,这为临床放疗中最大限度减少放疗副作用,根治肿瘤提供了一条新的研究思路.

AIM: To observe the oxidative injury of livers induced by local irradiation and the protection of antioxidants compound of Chinese drug in rats with tumor. METHODS: The Spraue-Dawley (SD) rats were divided into negative control group and trial groups. The tumor cells (Walker-256) were injected into the rat to get the solid tumor, which was then cut into small pieces to be embedded into the right rear buttocks under skin of rats. As the embedded tumor grew up successfully, the rats with solid tumor were randomly divided into 3 groups, i.e. tumor group, irradiative group and protective group. The protective group was given antioxidants compound by gav-age and other groups were given the same dosage water. The irradiative group and the protective group were locally γ-irradiated with the total doses of 47Gy, then all the rats were killed, the serum and livers were collected to measure the content of malondialdehyde (MDA), the activities of glutathione S-transferase (GST), total super-oxide dismutase (T-SOD), manganese superoxide dismutase (Mn-SOD), the total antioxidant capacity (TAC), nitric oxide (NO), nitric oxide synthase (NOS) and the total proteins. RESULTS: The activities of serum and liver GST (μkat/L and μkat/g) and the content of MDA (in liver protein, nmoL/g) in irradiative group were much higher than those in all the other groups (479 ± 17 vs 427±59 and 421±36, 50.3 ± 1.0 vs 46.8 ± 2.3 and 47.5 ± 1.0, 33.7 ± 8.8 vs21.4 ± 7.2 and 21.7 ± 6.8, P<0.05, P<0.01, P <0.01,respectively). The activities of T-SOD (in liver protein, μkat/g), Mn-SOD (in liver protein, μkat/g), GSH (in liver protein, mg/g) and TAC (in liver protein, μkat/g) in irradiative group were much lower than those in other groups (39.3 ± 7.0 vs 48.8 ± 2.8 and 47.7 ± 4.3, 18.7 ± 6.2 vs 28.8 ± 2.5 and 28.2 ± 7.7, 0.44 ± 0.13 vs 0.57 ± 0.06 and 0.61 ± 0.22, 20.7 ± 5.3 vs 26.5 ± 3.3 and 26.3 ±1.7, P<0.01, P<0.01, P<0.01, P<0.05, respectively) The content of NO (in liver protein, μmoL/g) in irradiative group increased significantly, the activity (in liver protein, μkat/g) of NOS also increased significantly than those in the control group (1.22 ± 0.08 vs 0.98 ± 0.15, 4.92 ± 0.94 vs 3.63 ± 0.77,P<0.01, P<0.05, respectively). The content of NO and the activity of NOS in protective group decreased markedly than those in irradiative group (0.77 ± 0.22 vs 1.22 ± 0.08, 3.62 ± 0.49 vs 4.92 ± 0.94, P<0.01, P<0.05, respectively). CONCLUSION: Local irradiation can cause the oxidative injury on liver of the rats and the antioxidant compound shows good protective effect against this injury by increasing the activities of antioxidants and decreasing the content of NO, the activity and expression of NOS, which give us a new way to reduce the side effect during the radiotherapy.