广西医学

目的探讨沉默吲哚胺2，3⁃双加氧酶（IDO）对肝癌荷瘤小鼠的肿瘤生长及免疫功能的影响。方法构建H22肝癌荷瘤小鼠模型，将其分为空白对照组、scramble⁃短发夹RNA（shRNA）对照组、IDO⁃shRNA治疗组，各5只。对IDO⁃shRNA治疗组、scramble⁃shRNA对照组小鼠采用尾静脉快速高压注射法分别注射50 μg IDO⁃shRNA质粒及50 μg scramble⁃shRNA质粒，空白对照组小鼠采用以相同方式注射等量0.9%氯化钠溶液，共干预3次。观察并记录各组小鼠的肿瘤形成时间、肿瘤体积，于末次注射后48 h处死小鼠，称取肿瘤的重量。采用HE染色观察小鼠肿瘤组织病理学变化；采用流式细胞术检测肝癌荷瘤小鼠脾脏T淋巴细胞百分比、T淋巴细胞凋亡率、Treg百分比；采用ELISA检测肝癌荷瘤小鼠肿瘤组织中肿瘤坏死因子α（TNF⁃α）、γ干扰素（IFN⁃γ）、白细胞介素（IL）⁃2、IL⁃10水平。结果与scramble⁃shRNA组、空白对照组相比，IDO⁃shRNA治疗组小鼠的肿瘤形成时间延迟、肿瘤重量减少、肿瘤体积减小，肿瘤组织中的细胞数目减少且出现不同程度的片状坏死，脾脏内CD4+ T淋巴细胞百分比、CD4+/CD8+值及肿瘤组织中IFN⁃γ和IL⁃2水平升高，脾脏内CD4+ T淋巴细胞凋亡率、CD8+ T淋巴细胞凋亡率、Treg百分比及肿瘤组织中TNF⁃α和IL⁃10水平降低（P<0.05）。结论尾静脉快速高压注射IDO⁃shRNA可有效抑制肝癌荷瘤小鼠的肿瘤生长，其作用机制与提高机体抗肿瘤免疫反应有关。

Objective To investigate the effect of silencing indoleamine 2,3⁃dioxygenase (IDO) on tumor growth and immune function in mice bearing hepatocellular carcinoma. Methods H22 hepatocellular carcinoma⁃bearing mouse models were established and divided into blank control group, scramble⁃short hairpin RNA (shRNA) control group, or IDO⁃shRNA treatment group, with 5 mice in each group. Mice in the IDO⁃shRNA treatment group and the scramble⁃shRNA control group received rapid high⁃pressure tail vein injections of 50 μg IDO⁃shRNA plasmid and 50 μg scramble⁃shRNA plasmid, respectively. Mice in the blank control group received an equal volume of 0.9% sodium chloride solution injected in the same manner. The intervention was performed three times. Tumor formation time and tumor volume were observed and recorded. Mice were sacrificed 48 hours after the last injection, and tumor weight was measured. Histopathological changes in tumor tissues were observed by HE staining. Flow cytometry was used to detect the percentage of splenic T lymphocytes, T lymphocyte apoptosis rate, and the percentage of Treg in the mice. Levels of tumor necrosis factor alpha (TNF⁃α), interferon gamma (IFN⁃γ), interleukin (IL)⁃2, and IL⁃10 in tumor tissues of mice bearing hepatocellular carcinoma were measured by ELISA. Results Compared with the scramble⁃shRNA group and the blank control group, the IDO⁃shRNA treatment group exhibited delayed tumor formation time, reduced tumor weight, decreased tumor volume, a reduced number of cells in tumor tissues with varying degrees of patchy necrosis, an increased percentage of CD4+ T lymphocytes, an increased CD4+/CD8+ value in the spleen, elevated levels of IFN⁃γ and IL⁃2 in tumor tissues, decreased apoptosis rates of CD4+ and CD8+ T lymphocytes, a reduced percentage of Treg in the spleen, and lower levels of TNF⁃α and IL⁃10 in tumor tissues (P<0.05). Conclusion Rapid high⁃pressure tail vein injection of IDO⁃shRNA can effectively inhibit tumor growth in hepatocellular carcinoma⁃bearing mice, and its mechanism is related to enhancing the body's anti⁃tumor immune response.

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