Necroptosis Inhibition Preserves Diaphragm Function in Experimental Sepsis.

Diaphragm dysfunction in sepsis remains a critical challenge in intensive care, yet its underlying mechanisms are poorly understood. This study investigates the role of necroptosis, a recently recognized form of programmed cell death, in sepsis-induced diaphragm dysfunction. A cecal ligation and puncture model in C57BL/6 mice was employed to induce sepsis. Diaphragm function was assessed through ultrasound imaging and pulmonary function testing. Necroptosis markers [receptor-interacting protein kinase (Ripk)-1, Ripk3, and mixed-lineage kinase domain-like protein (Mlkl)] and inflammatory cytokines [Il-6, tumor necrosis factor (Tnf)-α] were quantified using real-time quantitative RT-PCR, Western blot analysis, and enzyme-linked immunosorbent assay. The effect of the necroptosis inhibitor necrostatin-1 (Nec-1) was evaluated in vivo and in vitro. Septic mice exhibited significant diaphragm dysfunction correlated with an elevated expression of necroptosis markers and inflammatory cytokines in diaphragm tissue. Nec-1 treatment not only suppressed necroptosis but also markedly improved diaphragm function and respiratory parameters. In vitro, peritoneal lavage fluid from septic mice induced necroptosis in C2C12 myotubes, an effect mitigated by Nec-1. The findings unveil necroptosis as a key player in sepsis-induced diaphragm dysfunction. A novel mechanism is proposed in which Tnf-α, produced by activated peritoneal macrophages, triggers diaphragm necroptosis. This study not only advances the understanding of the pathophysiology of sepsis but also identifies necroptosis inhibition as a promising therapeutic strategy for preserving diaphragm function in sepsis.