目的 研究铁皮石斛Dendrobium officinale水提物对4T1乳腺癌荷瘤模型小鼠的抑瘤及免疫调节作用，并进一步探讨其作用机制。方法 采用BALB/c雌性小鼠构建4T1乳腺癌荷瘤小鼠模型后，随机分为模型组、盐酸表柔比星组(8 mL/kg)和铁皮石斛水提物低、中、高剂量(0.5、1.0、1.5 g/kg)组，另选10只正常BALB/c雌性小鼠作为对照组，给予相应药物进行干预，观察小鼠生存状态，每3天测量肿瘤直径与短径，连续给药28 d后处死小鼠，称定肿瘤质量，计算抑瘤率；采用小动物活体成像仪和转移灶计数观察肺部肿瘤转移情况；称定小鼠脾脏、胸腺质量，计算脏器系数；苏木素-伊红(HE)染色观察肿瘤、肺部以及脾脏形态学变化；血液分析仪检测荷瘤小鼠外周血中白细胞数目和淋巴细胞占比；ELISA法检测血清中白细胞介素-2(interleukin-2，IL-2)、γ干扰素(interferon-γ，IFN-γ)和肿瘤坏死因子-α(tumor necrosis factor-α，TNF-α)水平；流式细胞术检测外周血中T淋巴细胞比例；脾淋巴细胞增殖试验检测脾脏中T淋巴细胞、B淋巴细胞增殖能力；Western blotting检测肿瘤组织中磷脂酰肌醇3-激酶(phosphatidylinositol 3-kinase，PI3K)/蛋白激酶B(protein kinase B，Akt)/哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin，mTOR)通路相关蛋白表达。结果 与模型组比较，铁皮石斛水提物组小鼠肿瘤生长趋势放缓，肿瘤质量减轻(P＜0.01)，肿瘤组织坏死细胞增多，肿瘤以及肺部转移灶荧光强度显著降低(P＜0.05、0.01)，肺部转移灶数目减少(P＜0.05、0.01)；脾脏、胸腺指数增加(P＜0.05)；外周血中白细胞数目下降(P＜0.01)，淋巴细胞占比提高(P＜0.05、0.01)；血清中IL-2、IFN-γ、TNF-α水平增加(P＜0.05、0.01)；外周血中CD3⁺ T细胞占比升高(P＜0.05)，CD4⁺/CD8⁺值上升(P＜0.01)；脾脏中T淋巴细胞、B淋巴细胞增殖能力提高(P＜0.05)；肿瘤组织中PI3K/Akt/mTOR通路相关蛋白表达降低(P＜0.05、0.01)。结论 铁皮石斛水提物可显著抑制荷瘤小鼠肿瘤的生长与转移，恢复荷瘤小鼠免疫功能，其机制可能与下调PI3K/Akt/mTOR通路表达相关。

Objective To investigate the anti-tumor and immunomodulatory effects of Dendrobium officinale water extract on 4T1 breast cancer model mice, and further explore its mechanism. Methods BALB/c female mice were successfully used to establish a 4T1 breast cancer tumor-bearing mouse model. The mice were randomly divided into model group, epirubicin hydrochloride (8 mL/kg) group and D. officinale water extract low-, medium-, and high-dose (0.5, 1.0, 1.5 g/kg) groups, and 10 normal BALB/c female mice were selected as control group. Corresponding drugs were given to intervene, survival state of mice was observed. The tumor diameter and short diameter were measured every three days. After continuous administration for 28 d, mice were sacrificed, tumor weight was weighed, and tumor inhibition rate was calculated. Lung tumor metastasis was observed by living animal imager and counting of metastases. Spleen and thymus were weighed and organ coefficients were calculated. HE staining was used to observe the morphological changes of tumor, lung and spleen. The number of white blood cells and proportion of lymphocytes in peripheral blood of tumor-bearing mice were detected by hematology analyzer. The levels of interleukin-2 (IL-2), γ interferon (IFN-γ) and tumor necrosis factor-α (TNF-α) in serum were detected by ELISA. The proportion of T lymphocytes in peripheral blood was detected by flow cytometry. Splenic lymphocyte proliferation test was used to detect the proliferation of T lymphocytes and B lymphocytes in spleen. The expressions of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway related proteins in tumor tissues were detected by Western blotting. Results Compared with model group, tumor growth trend of D. officinale water extract group was slowed down, tumor weight was reduced (P < 0.01), necrotic cells in tumor tissues were increased, fluorescence intensity of tumor and lung metastases was significantly decreased (P < 0.05, 0.01), and number of lung metastases was decreased (P < 0.05, 0.01). Spleen and thymus index were increased (P < 0.05). The number of white blood cells in peripheral blood was decreased (P < 0.01), and proportion of lymphocytes was increased (P < 0.05, 0.01). The levels of IL-2, IFN-γ and TNF-α in serum were increased (P < 0.05, 0.01). CD3⁺T lymphocytes in peripheral blood was increased (P < 0.05), CD4⁺/CD8⁺ ratio was increased (P < 0.01); Proliferation ability of T lymphocytes and B lymphocytes in spleen were increased (P < 0.05). The expressions of PI3K/Akt/mTOR pathway related proteins in tumor tissues were decreased (P < 0.05, 0.01). Conclusion D. officinale water extract can significantly inhibit tumor growth and metastasis in tumor-bearing mice, and restore immune function in tumor-bearing mice, which may be related to down-regulation of PI3K/Akt/mTOR pathway expression.

国家重点研发计划项目(2017YFC1702203)；浙江省中医药科技计划项目(2022ZB095)；浙江省省级重点实验室项目(2012E10002)