Cellular senescence contributes to mechanical ventilation-induced diaphragm dysfunction by upregulating p53 signalling pathways

Mechanical ventilation can cause acute atrophy and injury in the diaphragm, which are related to adverse clinical

In a rabbit model, we demonstrated that mechanical ventilation in A/C mode for 48 h can still significantly induce ultrastructural damage and atrophy of the diaphragm. Moreover, p53-dependent senescence might play a role in mechanical ventilation-induced dysfunction. These findings might provide novel therapeutic targets for VIDD.

A total of twelve New Zealand rabbits were randomly divided into 2 groups: (1) spontaneously breathing anaesthetized animals (the CON group) and (2) mechanically ventilated animals (for 48 h) in V-ACV mode (the MV group). Respiratory parameters were collected during ventilation. Diaphragm were collected for further analyses.

Compared to those in the CON group, the percentage and density of sarcomere disruption in the MV group were much higher (p < 0.001, both). The mRNA expression of MAFbx and MuRF1 was upregulated in the MV group (p = 0.003 and p = 0.006, respectively). Compared to that in the CON group, the expression of MAFbx and MuRF1 detected by western blotting was also upregulated (p = 0.02 and p = 0.03, respectively). Moreover, RNA-seq showed that genes associated with senescence were remarkably enriched in the MV group. The mRNA expression of related genes was further verified by q-PCR (Pai1: p = 0.009; MMP9: p = 0.008). Transverse cross-sections of diaphragm myofibrils in the MV group showed more intensive positive staining of SA-βGal than those in the CON group. p53-p21 axis signalling was elevated in the MV group. The mRNA expression of p53 and p21 was significantly upregulated (p = 0.02 and p = 0.05, respectively). The western blot results also showed upregulation of p53 and p21 protein expression (p = 0.03 and p = 0.05, respectively). Moreover, the p21-positive staining in immunofluorescence and immunohistochemistry in the MV group was much more intense than that in the CON group (p < 0.001, both). Conclusions: In a rabbit model, we demonstrated that mechanical ventilation in A/C mode for 48 h can still significantly induce ultrastructural damage and atrophy of the diaphragm. Moreover, p53-dependent senescence might play a role in mechanical ventilation-induced dysfunction. These findings might provide novel therapeutic targets for VIDD.