FIGURE 5.

Nucleotide‐binding domain and leucine‐rich‐repeat‐containing protein X1 decreases with age and NLRX1 deficiency accelerates aging lung‐like structural and functional changes. (a) Real‐time PCR to detect the expression levels of Nlrx1 mRNA in lungs of 3‐ or 12‐ or 24‐month‐old (mo) wild‐type (WT) mice. (b) Immunoblot to detect NLRX1 in lungs of 3‐ or 12‐ or 24‐months WT mice. (c) Densitometry evaluation of the NLRX1 protein expression levels (3‐months, n = 9; 12‐months, n = 9; 24‐months, n = 7). (d) Representative images of H&E‐stained lung sections from WT or NLRX1 knockout (KO) mice. Scale bars, 200 μm. (e) Quantification of mean chord length (μm) is shown in the graphs, and (f) Total cell recovery of bronchoalveolar lavage (BAL) fluids from WT or NLRX1 KO mice. Each group n = 5 mice except 24‐months NLRX1 KO (n = 4). For (g–o), pulmonary function tests from 3‐ or 6‐ or 16‐ or 24‐months WT or NLRX1 KO mice were measured by flexiVent system. WT or NLRX1 KO 3‐months, n = 7; WT or NLRX1 KO 6‐months, n = 6; WT or NLRX1 KO 16‐months, n = 8; WT 24‐months, n = 7; NLRX1 KO 24‐months, n = 4. * Note: Two of six NLRX1 KO mice allocated for the 24‐months group succumbed to natural death during the follow‐up period. (g–i) Pressure‐volume loop at indicated timepoints. (j) Inspiratory capacity (IC), (k) Dynamic compliance of respiratory system (Crs), (l) Static compliance of respiratory system (Cst), (m) elastance of respiratory system (Ers), (n) tissue elastance (H), and (o) tissue damping (g). * Note: Significance included in the graph indicated only the difference between the WT and KO groups. Refer to Figure S2 for the difference in significance within each group. Error bars indicate means ± SEM. Data were analyzed by ordinary one‐way ANOVA followed by Tukey's multiple comparisons test (a and c), or two‐way ANOVA followed by Tukey's multiple comparisons test (e–o). ***p < 0.005, **p < 0.01, *p < 0.05. N.S. means not significant