目的:制备心肌特异性多肽（PCM）修饰介孔硅纳米粒（MSN）包载精氨酸（LA）的纳米颗粒（PCM-MSN@LA），评价其对脓毒症心肌的特异性保护作用。方法:通过缩合反应制备PCM-MSN@LA，检测PCM-MSN@LA表征、LA修饰量和释放量，观察PCM-MSN@LA的细胞吞噬行为及其对组织的亲和力。①实验一：将SD乳鼠原代心肌细胞分为正常对照组（Con组）、脂多糖（LPS）组、精氨酸纳米粒组（MSN@LA/LPS组）、心肌靶向精氨酸纳米粒组（PCM-MSN@LA/LPS组）。LPS组用5 mg/L LPS刺激细胞16 h；MSN@LA/LPS组和PCM-MSN@LA/LPS组分别用含25 mg/L LA的MSN@LA及PCM-MSN@LA与LPS共同刺激细胞16 h。测定细胞活性和活性氧（ROS）产生水平；用原位末端缺刻标记法（TUNEL）检测细胞凋亡情况；用蛋白质免疫印迹试验（Western Blot）检测内皮型一氧化氮合酶（eNOS）、诱导型一氧化氮合酶（iNOS）蛋白表达。②实验二：按照随机数字表法将64只健康雄性C57BL/6小鼠分为假手术组（Sham组）、LPS组、MSN@LA/LPS组和PCM-MSN@LA/LPS组，每组16只。LPS组腹腔注射50 mg/kg LPS；MSN@LA/LPS组和PCM-MSN@LA/LPS组腹腔注射LPS后立即经尾静脉分别注射0.5 mg/kg的MSN@LA及PCM-MSN@LA。每组8只小鼠用于观察24 h存活情况；另外8只于术后12 h用超声心动图评价心功能，用实时荧光定量聚合酶链反应（RT-qPCR）测定心肌组织白细胞介素（IL-1、IL-6）、肿瘤坏死因子-α（TNF-α）的mRNA表达。结果:PCM-MSN@LA呈球形，粒径约180 nm，Zeta电位约-21 mV，且可负载LA，LA修饰量及释放率分别为12.3%、24.3%，细胞吞噬实验显示PCM-MSN@LA具有心肌细胞和心肌组织靶向性。实验一：LPS刺激后心肌细胞活性下降，ROS生成增多，凋亡增多，eNOS及iNOS蛋白表达增多。与LPS组比较，MSN@LA/LPS组和PCM-MSN@LA/LPS组细胞活性增高，ROS及凋亡减少，eNOS、iNOS表达增多；且PCM-MSN@LA/LPS组较MSN@LA/LPS组可进一步提高细胞活性，减少ROS产生和细胞凋亡，增加eNOS、iNOS蛋白表达〔细胞活性（n A值）：0.51±0.08比0.41±0.03，ROS水平（相对荧光强度）：28 450±1 941比35 628±2 551，凋亡细胞/总细胞数：0.27±0.03比0.35±0.04，eNOS/β-Tubulin：1.467±0.046比1.201±0.131，iNOS/β-Tubulin：1.700±0.033比1.577±0.068，均n P<0.05〕。实验二：MSN@LA/LPS组和PCM-MSN@LA/LPS组术后24 h存活动物数多于LPS组（只：2、4比1，n P值分别为0.36、0.03）。与Sham组比较，LPS组小鼠心功能明显下降，心肌组织炎性因子mRNA表达增多。与LPS组比较，PCM-MSN@LA/LPS组左室射血分数（LVEF）、左室短轴缩短率（LVFS）明显升高，IL-1、IL-6、TNF-α的mRNA表达明显下降〔LVEF：0.456±0.019比0.337±0.017，LVFS：（21.97±1.78）%比（15.53±1.67）%，IL-1 mRNA（2n -ΔΔCT）：169.22±8.95比189.79±6.79，IL-6 mRNA（2n -ΔΔCT）：19.90±1.60比23.74±1.45，TNF-α mRNA（2n -ΔΔCT）：8.21±0.81比11.00±1.48，均n P<0.05〕；而MSN@LA/LPS组与LPS组各指标比较差异无统计学意义。n 结论:PCM-MSN@LA具有心肌靶向性，可显著提高心肌细胞活性，下调炎性因子表达，减少ROS产生，减轻脓毒症心功能不全，从而实现脓毒症心肌损伤的靶向治疗。“,”Objective:To prepare primary cardiomyocyte (PCM) specific peptide-conjugated mesoporous silicon nanoparticles (MSN) with L-arginine (LA) as a core (PCM-MSN@LA), and evaluate its specific protective effect on septic myocardium.Methods:PCM-MSN@LA was prepared by condensation reaction, the characterization of PCM-MSN@LA, the amount of LA modification and release was detected, and the phagocytosis of PCM-MSN@LA and its affinity to myocardial tissue was observed. ① Experiment one: SD neonatal rat cardiomyocytes were divided into control group (Con group), lipopolysaccharide (LPS) group, MSN@LA/LPS group and PCM-MSN@LA/LPS group. The LPS group was stimulated with 5 mg/L LPS for 16 hours, while the MSN@LA/LPS group and PCM-MSN@LA/LPS group were treated with 5 mg/L LPS and 25 mg/L LA-containing nanoparticles (MSN@LA and PCM-MSN@LA) for 16 hours. Cell viability and reactive oxygen species (ROS) production levels were detected. Apoptosis was observed via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method (TUNEL). Western Blot was used to detect the changes in endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) proteins. ② Experiment two: 64 healthy male C57BL/6 mice were divided into Sham group, LPS group, MSN@LA/LPS group and PCM-MSN@LA/LPS group by random number table method, 16 mice in each group. LPS group were injected 50 mg/kg LPS intraperitoneally. MSN@LA/LPS group and PCM-MSN@LA/LPS group were injected with 0.5 mg/kg MSN@LA and PCM-MSN@LA via tail vein immediately after intraperitoneal injection of LPS. Eight animals in each group were used to observe the 24-hour survival rate, and the other 8 mice were used to detect cardiac function by echocardiography at 12 hours after operation; mRNA expressions of interleukin (IL-1, IL-6) and tumor necrosis factor-α (TNF-α) were measured by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR).Results:PCM-MSN@LA was spherical, with particle size of about 180 nm, Zeta potential of about -21 mV, with LA loaded. The amount of LA modification and release rate were 12.3% and 24.3%, respectively. Cell phagocytosis experiments showed that PCM-MSN@LA had the targeting ability of cardiomyocytes and myocardial tissue. Experiment one: after LPS stimulation of myocardial cells, cell viability decreased, while ROS generation, apoptosis, eNOS and iNOS protein expressions increased. Compared with LPS group, MSN@LA/LPS group and PCM-MSN@LA/LPS group had higher cell viability, reduced ROS levels and apoptosis, increased expressions of eNOS and iNOS. PCM-MSN@LA/LPS group changed the above effect further than MSN@LA/LPS group [cell viability (n A value): 0.51±0.08 vs. 0.41±0.03, ROS (relative fluorescence intensity): 28 450±1 941 vs. 35 628±2 551, TUNEL positive cells/total cells: 0.27±0.03 vs. 0.35±0.04, eNOS/β-Tubulin: 1.467±0.046 vs. 1.201±0.131, iNOS/β-Tubulin: 1.700±0.033 vs. 1.577±0.068, alln P < 0.05]. Experiment two: the number of 24-hour survive in MSN@LA/LPS group and PCM-MSN@ LA/LPS group were higher than LPS group (number: 2, 4 vs. 1, n P values were 0.36 and 0.03 respectively). Compared with Sham group, the cardiac function of LPS group was significantly inhibited and the mRNA expression of inflammatory factors increased. The PCM-MSN@LA/LPS group had higher left ventricular ejection fraction (LVEF) and left ventricular short-axis shortening rate (LVFS) than LPS group, and lower mRNA expressions of IL-1, IL-6, and TNF-α mRNA [LVEF: 0.456±0.019 vs. 0.337±0.017, LVFS: (21.97±1.78)% vs. (15.53±1.67)%, IL-1 mRNA (2n -ΔΔCT): 169.22±8.95 vs. 189.79±6.79, IL-6 mRNA (2n -ΔΔCT): 19.90±1.60 vs. 23.74±1.45, TNF-α mRNA (2n -ΔΔCT): 8.21±0.81 vs. 11.00±1.48, all n P < 0.05]. There was no significant difference in each index between the MSN@LA/LPS group and LPS group.n Conclusion:PCM-MSN@LA with myocardial targeting characteristic significantly increased the activity of myocardial cells, down-regulated the expression of inflammatory factors and the production of ROS, alleviated cardiac insufficiency in sepsis, and achieved the targeted treatment of myocardial injury in sepsis.