羧基化介孔二氧化硅纳米颗粒递送PD-L1抑制剂治疗膀胱癌的作用研究

摘要 目的：构建羧基化介孔二氧化硅纳米颗粒（COOH-MSN）递送PD-L1抑制剂治疗膀胱癌。方法：构建负载PD-L1抑制剂的COOH-MSNs，透射电镜检测纳米颗粒的特征，zeta电位分析仪检测纳米颗粒的电位变化；流式细胞术检测血液中T细胞和CD8⁺T细胞的比例；MTT实验检测细胞增殖；构建小鼠荷瘤模型，HE染色检测基本的病理学变化，免疫组化检测ki-67的表达。结果：透射电镜结果显示纳米颗粒呈圆形，直径约为100 nm；COOH-MSNs表面带负电荷，BSA呈强负电性，BSA包封后纳米材料整体负电荷增强；纳米材料可显著提高T细胞和CD8⁺T细胞的比例，并进一步抑制膀胱癌细胞的增殖；动物实验结果显示纳米材料可抑制移植瘤的生长，且移植瘤内淋巴细胞的数量显著升高；免疫组化结果显示相对于PD-L1抑制剂组，纳米材料组ki-67增殖指数显著减低；HE染色结果显示PD-L1抑制剂组肾组织内可观察到血管充血、扩张和较多炎细胞浸润，而纳米材料组肾组织损伤程度显著降低。结论：我们构建了一种负载有PD-L1抑制剂的COOH-MSNs，可有效激活抗肿瘤免疫反应，并降低对正常器官的损伤。

Constructing Carboxylated Mesoporous Silica Nanoparticles to Deliver PD-L1 Inhibitors for the Treatment of Bladder Cancer

ABSTRACT Objective: To construct carboxylated mesoporous silica nanoparticles (COOH-MSN) to deliver PD-L1 inhibitors for the treatment of bladder cancer. Methods: COOH-MSNs loaded with PD-L1 inhibitor were constructed, the characteristics of nanoparticles were detected by transmission electron microscopy, and the potential changes of nanoparticles were detected by zeta potential analyzer. Flow cytometry was used to measure the proportion of T cells and CD8⁺T cells in the blood. Cell proliferation was detected by MTT assay. The mouse tumor-bearing model was constructed, the basic pathological changes were detected by HE staining, and the expression of ki-67 was detected by immunohistochemistry. Results: The results of transmission electron microscopy showed that the nanoparticles were round and the diameter was about 100 nm. The surface of COOH-MSNs was negatively charged, the BSA was strongly electronegative, and the overall negative charge of the nanomaterial was enhanced after the BSA encapsulation. The nanomaterials significantly increased the ratio of T cells and CD8⁺T cells, and further inhibited the proliferation of bladder cancer cells. The results of animal experiments showed that the nanomaterials inhibited the growth of transplanted tumors and the number of lymphocytes in transplanted tumors increased significantly. The results of immunohistochemistry showed that the ki-67 proliferation index decreased significantly in the nanomaterial group compared with the PD-L1 inhibitor group. HE staining showed that vascular congestion, dilatation, and more inflammatory cell infiltration were observed in the renal tissue of the PD-L1 inhibitor group, while the degree of renal tissue injury was significantly reduced in the nanomaterial group. Conclusion: We constructed a COOH-MSN loaded with PD-L1 inhibitors, which can effectively activate anti-tumor immune response and reduce damage to normal organs.