Obesity is a risk factor of many diseases, but could be beneficial to the individuals with bacterial infection. The present study was conducted to investigate the relationship between obesity and heart during nonfatal bacterial infection. Male normal (lean) and diet-induced obesity mice (DIO, fed with high-fat diet) were chosen to perform nasal instillation with E. coli to establish a nonfatal acute mouse model. The cardiac histopathology, inflammation and oxidative damage, as well as apoptosis were detected post-infection. The results revealed that the Escherichia coli (E.coli)-infected mice exhibited increased cardiac index, contents of IL-1β, IL-6, IL-8, TNF-α, leptin and resistin, levels of apoptotic proteins (caspase-3 and caspase-9, and bax/bcl-2 ratio), cardiac pathological changes and oxidative stress. Furthermore, these parameters were more serious in the lean mice than those in the DIO mice. In summary, our findings gave a new sight that E.coli infection impaired heart via histopathological lesions, inflammation and oxidative stress and excessive apoptosis of cardiomyocytes. Interestingly, obesity exerted attenuated effects on the heart of mice with non-fatal infection of E.coli through decreased inflammation, oxidative stress and apoptosis of cardiac tissue.

肥胖是许多疾病的危险因素，但可能对细菌感染者有益。本研究旨在调查非致命细菌感染期间肥胖与心脏之间的关系。选择雄性正常（瘦）和饮食诱导的肥胖小鼠（DIO，高脂饮食喂养）进行大肠杆菌鼻腔滴注，建立非致死性急性小鼠模型。感染后检测心脏组织病理学、炎症和氧化损伤以及细胞凋亡。结果表明，大肠杆菌（E.coli) 感染的小鼠表现出增加的心脏指数、IL-1β、IL-6、IL-8、TNF-α、瘦素和抵抗素的含量、凋亡蛋白 (caspase-3 和 caspase-9，以及 bax/bcl-2) 的水平比率）、心脏病理变化和氧化应激。此外，这些参数在瘦小鼠中比在 DIO 小鼠中更严重。总之，我们的研究结果提供了一个新的视角，即大肠杆菌感染通过组织病理学病变、炎症和氧化应激以及心肌细胞的过度凋亡来损害心脏。有趣的是，肥胖通过减少心脏组织的炎症、氧化应激和细胞凋亡，对非致命性大肠杆菌感染小鼠的心脏产生了减弱的影响。