Short courses of mechanical ventilation with high-O2 levels in elderly rat lungs

Abstract

Purpose:To evaluate the effects of mechanical ventilation (MV) of high-oxygen concentration in pulmonary dysfunction in adult and elderly rats. Methods: Twenty-eight adult (A) and elderly (E), male rats were ventilated for 1 hour (G-AV1 and G-EV1) or for 3 hours (G-AV3 and G-EV3). A and E groups received a tidal volume of 7 mL/kg, a positive end-expiratory pressure of 5 cm H2O, respiratory rate of 70 cycles per minute, and an inspiratory fraction of oxygen of 1. We evaluated total protein content and malondialdehyde in bronchoalveolar lavages (BAL) and performed lung histomorphometrical analyses. Results: In G-EV1 animals, total protein in BAL was higher (33.0±1.9 µg/mL) compared with G-AV1 (23.0±2.0 µg/mL). Upon 180 minutes of MV, malondialdehyde levels increased in elderly (G-EV3) compared with adult (G-AV3) groups. Malondialdehyde and total proteins in BAL after 3 hours of MV were higher in elderly group than in adults. In G-EV3 group we observed alveolar septa dilatation and significative increase in neutrofiles number in relation to adult group at 60 and 180 minutes on MV. Conclusion: A higher fraction of inspired oxygen in short courses of mechanical ventilation ameliorates the parameters studied in elderly lungs.

Effects of oxygen in lungs of rats

“…Another study indicates that higher fraction of inspired oxygen in short courses of mechanical ventilation ameliorates the parameters studied in elderly lungs. In elderly group observed alveolar septa dilatation and significative increase in neutrofiles 13 .…”

Association between Maturation and Aging and Pulmonary Responses in Animal Models of Lung Injury

“…89,90 Hyperoxia was the only pulmonary challenge in the middle aged/elderly, which was consistently associated with an increased tolerance. 66 43 VILI ↓ ↓* ↔ Copland et al 44 VILI ↓ ↓ ↓ Chan et al 45 VILI NR NR ↓ Smith et al 46 VILI ↑ ↔ NR Cannizzaro et al 47 VILI + hyperoxia NR NR NR Yam et al 48 Hyperoxia 50 Hyperoxia ↓ NR NR Laudert et al 51 Hyperoxia ↓ ↓ ↓ Keeney et al 52 Hyperoxia ↓ ↓ ↓ Johnston et al 53 Hyperoxia ↓ ↓ ↓ D'Angio et al 54 Hyperoxia NR ↓ ↓ Berkelhamer et al 55 Hyperoxia NR NR ↓ Martin et al 56 LPS NR NR ↔ Lee et al 57 LPS NR NR NR Franco et al 58 LPS ↓ ↓ NR Bodas et al 59 LPS NR ↓ NR Smith et al 46 LPS ↔ ↔ NR Smith et al 46 LPS + VILI ↓ ↓ NR Martin et al 60 Pneumonia NR NR ↔ Sordelli et al 61 Pneumonia NR NR NR Martin et al 62 Pneumonia NR NR ↑ Garvy and Harmsen 63 Pneumonia NR NR ↑ 66 43 VILI ↓ ↓* ↔ Copland et al 44 VILI ↓ ↓ ↓ Chan et al 45 VILI NR NR ↓ Smith et al 46 VILI ↑ ↔ NR Cannizzaro et al 47 VILI + hyperoxia NR NR NR Yam et al 48 Hyperoxia 50 Hyperoxia ↓ NR NR Laudert et al 51 Hyperoxia ↓ ↓ ↓ Keeney et al 52 Hyperoxia ↓ ↓ ↓ Johnston et al 53 Hyperoxia ↓ ↓ ↓ D'Angio et al 54 Hyperoxia NR ↓ ↓ Berkelhamer et al 55 Hyperoxia NR NR ↓ Martin et al 56 LPS NR NR ↔ Lee et al 57 LPS NR NR NR Fran...…”

“…Data on the number of resident alveolar macrophages and neutrophils were conflicting. Independent of the model used, in most studies, the recruitment of neutrophils into the lung was lower in infants/juveniles 44,46,51,52,54,[56][57][58]60,61 (table 4) and higher in the middle aged/elderly 40,[65][66][67]69,[72][73][74][76][77][78][79][80][81]86,87,89 (table 5), compared with adults. In all age groups, cell influx was predominated by neutrophils.…”

“…73,78,82,83,88 In addition, macrophage function in the pneumonia models was impaired in these age groups and associated with a decreased clearance of bacteria (tables 4 and 5). Although data were limited, an 65 VILI ↑ ↑ ↑ Moitra et al 40 VILI ↑ NR NR Cavassani et al 66 VILI + hyperoxia ↑ ↑ NR Andrade et al 67 VILI + hyperoxia ↑ ↑ NR Choi et al 68 Hyperoxia 69 Hyperoxia ↔ ↔ ↓ Otterbein et al 70 Hyperoxia ↓ ↓ ↓ Brock and Di Giulio 71 Hyperoxia NR NR ↔ Otterbein et al 70 Hyperoxia + LPS NR NR ↑ Elder et al 72 LPS ↔ NR NR Ito et al 73 LPS ↑ ↔ ↑ Ito et al 74 LPS ↑ NR ↔ Chiu et al 75 LPS NR NR NR Moitra et al 40 LPS ↑ NR NR Ren et al 76 LPS ↑ ↑ NR Esposito and Pennington 77 Pneumonia NR NR ↔ Yokota et al 78 Pneumonia NR NR ↑ Esposito et al 79 Pneumonia NR NR ↔ Antonini et al 80 Pneumonia ↑ ↑ ↑ Hinojosa et al 81 Pneumonia ↑ ↑ ↑ Mares et al 83 Pneumonia NR ↓ ↓ Mares et al 82 Pneumonia ↑ ↑ ↔ Rottinghaus et al 84 Pneumonia NR NR NR Shivshankar et al 85 Pneumonia NR NR ↑ Boyd et al 86 Pneumonia ↑ ↑ ↑ Chen et al 87 Pneumonia NR NR ↑ Wen et al 88 Pneumonia 90 Bleomycin NR ↑ NR increased oxidative stress response was found in middle aged/ elderly 66,67,72,80 when compared with adults. Moreover, three hyperoxia models showed that the expression of antioxidants was increased in the infant/juvenile animals, which correlated with increased tolerance to hyperoxia.…”

Hyperoxia provokes a time- and dose-dependent inflammatory response in mechanically ventilated mice, irrespective of tidal volumes

“…These responses have repeatedly been documented in rodents following hyperoxic exposure in inhalation chambers [9–15]. Although hyperoxia has been suggested to induce time-dependent inflammatory responses [10], studies in animals are usually restricted to periods of up to 6 h of mechanical ventilation, limiting its clinical applicability [16–19]. Furthermore, the interaction between mechanical ventilation and concurrent hyperoxia may transcend lung injury by alveolar distention alone [9, 17, 20–22].…”