PD-1抑制剂对心肌炎症微环境及放射性损伤影响的实验研究北大核心CSCD

目的从免疫微环境的角度初探PD-1抑制剂对小鼠心肌损伤的影响及其潜在机制。方法建立小鼠放射性心肌损伤(RIMI)模型, 将20只C57BL/6小鼠随机分为4个组, 每组5只。A组为对照组;B组为PD-1抑制剂组;C组为单纯照射组, 心脏单次照射15 Gy;D组为照射+PD-1抑制剂组。照射后1个月麻醉处死小鼠, HE和Masson染色观察心肌组织形态学改变和评估心肌纤维化;流式细胞术检测心肌CD3+、CD3+CD4+、CD3+CD8淋巴细胞亚群及细胞因子(IL-4、IL-6、IL-17A、TNF-α、TGF-β1、INF-γ)水平;TUNEL检测心肌细胞凋亡率。结果照射后1个月, B组未见明显的心肌纤维化表现, C组和D组可见胶原纤维分布于心肌细胞间质。A、B、C、D组心肌胶原容积分数(CVF)分别为(1.97±0.36)%、(2.83±1.03)%、(5.39±0.77)%、(7.72±1.43)%, A组与B组间的CVF相似(P=0.314), 其余各组间均不同(均P<0.05)。与A组比较, B、C、D组的CD3+T淋巴细胞的绝对值和百分比均增高(均P<0.01), D组高于B组和C组(均P<0.01);A、C、B、D组的CD3+CD4+T淋巴细胞的绝对值和百分比相近(均P>0.05);D组的CD3+CD8+T淋巴细胞的绝对值和百分比都高于A、B、C组(P<0.001)。D组的IL-6、IL-17A、TGF-β1水平均高于A、B、C组(均P<0.001)。A、B、C、D组的凋亡指数逐渐增加, 各组间比较差异均有统计学意义(均P<0.001)。结论 PD-1抑制剂可通过促进心肌免疫炎症反应加重RIMI。

Experimentation of effect of PD-1 inhibitor on myocardial inflammation microenvironment and radiation-induced injury

Objective To explore the potential mechanism of PD-1 inhibitor P on RIMI from the perspective of immune microenvironment. Methods To establish a mouse model of radiation-induced myocardial injury (RIMI), twenty C57BL/6 mice were randomly divided into 4 groups, 5 in each group. Group A was the healthy control group;Group B was the PD-1 inhibitor group;Group C was the simple irradiation group, with a heart irradiation of 15Gy;Group D was the irradiation+ PD-1 inhibitor group. One month after irradiation, the mice were anesthetized and sacrificed. The morphological changes of myocardial tissues were observed by HE staining. The myocardial fibrosis was assessed by Masson staining. CD⁺₃, CD⁺₃CD⁺₄, CD⁺₃CD₈ lymphocyte subsets and cytokines (IL-4, IL-6, IL-17A, TNF-α, TGF-β1 and INF-γ) levels were determined by flow cytometry. The apoptosis rate of myocardial cells was detected by TUNE. Results One month after irradiation, there was no obvious myocardial fibrosis in group B, and collagen fibers were distributed in the interstitium of myocardial cells in groups C and D. Semi-quantitative analysis results showed that the myocardial collagen volume fraction (CVF) of groups A, B, C and D were (1.97±0.36)%,(2.83±1.03)%,(5.39±0.77)% and (7.72±1.43)%, respectively. The CVF between group A and group B was similar (P=0.314), and the differences in CVF between the other groups were statistically significant (all P<0.05). Compared with group A, the absolute value and percentage of CD⁺₃ T lymphocytes were significantly increased in groups B, C and D (all P<0.01). The values in group D were significantly higher than those in group B and group C (all P<0.01);The absolute value and percentage of CD⁺₃CD4 T lymphocytes were similar among four groups (all P>0.05);The absolute value and percentage of CD⁺₃CD₈ T lymphocytes in group D were significantly higher than those in groups A,B and C (all P<0.001). The expression levels of IL-6, IL-17A, and TGF-β1 in group D were significantly higher compared with those in groups A, B and C (all P<0.001). The apoptotic index was gradually increased in four groups, and the differences in apoptotic index among four groups were statistically significant (all P<0.001). Conclusion PD-1 inhibitors can aggravate RIMI by promoting myocardial immune inflammatory response.