益母草碱对结肠癌荷瘤小鼠肿瘤生长和免疫功能的影响

Impacts of leonurine on tumor growth and immune function in colon cancer bearing mice

目的 探讨益母草碱对结肠癌荷瘤小鼠肿瘤生长和免疫功能的影响。方法 C57BL/6小鼠建立结肠癌荷瘤小鼠模型,造模后的小鼠随机分为对照组(0.9%NaCl)、低剂量实验组(180 ng·g^(-1)益母草碱)、高剂量实验组(360 ng·g^(-1)益母草碱)、高剂量+空载组(360 ng·g^(-1)益母草碱+空载质粒)、高剂量+cGAS敲低组(360 ng·g^(-1)+cGAS siRNA质粒)。分组处理后测定肿瘤体积与质量,以免疫组化染色检测肿瘤组织环状GMP-AMP合成酶(cGAS)、干扰素基因刺激因子(STING)相对阳性表达及CD4^(+)T与CD8^(+)T阳性细胞数,以细胞计数试剂盒8法检测小鼠CD4^(+)T与CD8^(+)T细胞对肿瘤细胞杀伤率。结果 对照组、高剂量实验组、高剂量+空载组、高剂量+cGAS敲低组小鼠的肿瘤体积分别为(1 088.32±70.82)、(468.20±24.28)、(480.01±23.78)和(998.99±32.84)mm~3,cGAS相对阳性表达分别为1.00±0.00、5.18±0.73、5.30±0.80和1.12±0.46,STING相对阳性表达分别为1.00±0.00、5.64±0.81、5.48±0.75和1.14±0.50,CD4^(+)T阳性细胞数分别为(40.25±5.82)、(118.64±15.30)、(113.25±16.65)和(48.74±7.10)个,CD8^(+)T阳性细胞数分别为(49.76±6.12)、(143.68±16.80)、(135.75±17.42)和(57.01±8.24)个。高剂量实验组、高剂量+空载组的上述指标与对照组比较,在统计学上差异均有统计学意义(均P<0.05);高剂量+cGAS敲低组的上述指标与高剂量实验组比较,在统计学上差异均有统计学意义(均P<0.05)。结论 益母草碱可通过激活cGAS-STING信号而增强结肠癌荷瘤小鼠淋巴细胞增殖能力,抑制小鼠肿瘤生长。

Objective To investigate the effects of leonurine on tumor growth and immune function of colon cancer tumor bearing mice.Methods C57BL/6 mice were established a colon cancer bearing mouse model.After modeling,the mice were randomly divided into control group(0.9% NaCl),experimental-L group(180 ng·g^(-1 )leonurine),experimental-H group(360 ng·g^(-1) Leonurine),experimental-H + NC group(360 ng·g^(-1) leonurine + no-load plasmid),and experimental-H + sicGAS group(360 ng·g^(-1) leonurine +cGAS siRNA plasmid).Tumor volume and weight were measured after group treatment.Immunohistochemical staining was used to detect the relative positive expression of cyclic GMP-AMP synthase(cGAS),stimulator of interferon gene(STING) and the average positive number of CD4^(+)T and CD8^(+)T cells in tumor tissues.The killing rate of mouse CD4^(+)T and CD8^(+)T cells to tumor cells was detected by cell counting kit 8.Results The tumor volume of control group,experimental-H group,experimental-H + NC group and experimental-H + cGAS knockout group were(1 088.32 ± 70.82),(468.20 ± 24.28),(480.01 ± 23.78) and(998.99 ± 32.84) mm~3,respectively;the relative positive expressions of cGAS were 1.00 ± 0.00,5.18 ± 0.73,5.30 ± 0.80 and 1.12 ± 0.46,respectively;the relative positive expressions of STING were 1.00 ± 0.00,5.64 ± 0.81,5.48 ± 0.75 and 1.14 ± 0.50,respectively;the mean CD4^(+)T positive cells were 40.25 ± 5.82,118.64 ± 15.30,113.25 ± 16.65 and 48.74 ± 7.10,respectively;the average number of CD8^(+)T positive cells were 49.76 ± 6.12,143.68 ± 16.80,135.75 ± 17.42 and 57.01 ± 8.24,respectively.The above indexes in experimental-H group and experimental-H + no-load group were statistically significant compared with control group(all P < 0.05);there were statistically significant differences in the above indexes between the experimental-H + sicGAS group and the experimental-H group(all P < 0.05).Conclusion Leonurine can enhance the proliferation ability of lymphocytes in colon cancer tumor bearing mice by activating cGAS-STING signal,and inhibit tumor growth in mice.