Stress amplifies lung tissue mechanics, inflammation and oxidative stress induced by chronic inflammation.
BACKGROUND
Mechanisms linking behavioral stress and inflammation are poorly understood, mainly in distal lung tissue.


OBJECTIVE
We have investigated whether the forced swim stress (FS) could modulate lung tissue mechanics, iNOS, cytokines, oxidative stress activation, eosinophilic recruitment, and remodeling in guinea pigs (GP) with chronic pulmonary inflammation.


METHODS
The GP were exposed to ovalbumin or saline aerosols (2×/wk/4wks, OVA, and SAL). Twenty-four hours after the 4th inhalation, the GP were submitted to the FS protocol (5×/wk/2wks, SAL-S, and OVA-S). Seventy-two hours after the 7th inhalation, lung strips were cut and tissue resistance (Rt) and elastance (Et) were obtained (at baseline and after OVA and Ach challenge). Strips were submitted to histopathological evaluation.


RESULTS
The adrenals' weight, the serum cortisol, and the catecholamines were measured. There was an increase in IL-2, IL-5, IL-13, IFN-γ, iNOS, 8-iso-PGF2α, and in %Rt and %Et after Ach challenge in the SAL-S group compared to the SAL one. The OVA-S group has had an increase in %Rt and %Et after the OVA challenge, in %Et after the Ach and in IL-4, 8-iso-PGF2α, and actin compared to the OVA. Adrenal weight and cortisol serum were increased in stressed animals compared to nonstressed ones, and the catecholamines were unaltered.


CONCLUSIONS
Repeated stress has increased distal lung constriction, which was associated with an increase of actin, IL-4, and 8-iso-PGF2α levels. Stress has also induced an activation of iNOS, cytokines, and oxidative stress pathways.
Medicine Department LIM, School of Medicine, University of São Paulo, São Paulo, Brazil.
Fabiana G
FG
Reis
Ricardo H
RH
Marques
Claudia M
CM
Starling
Rafael
R
Almeida-Reis
Rodolfo P
RP
Vieira
Claudia T
CT
Cabido
Luiz Fernando F
LF
Silva
Tatiana
T
Lanças
Marisa
M
Dolhnikoff
Mílton A
MA
Martins
Edna A
EA
Leick-Maldonado
Carla M
CM
Prado
Iolanda F L C
IF
Tibério
D000199:Actins / Q000032:analysis; D000311:Adrenal Glands / Q000033:anatomy & histology; D000403:Airway Resistance / Q000502:physiology; D000818:Animals; D002395:Catecholamines / Q000097:blood; D002908:Chronic Disease; D016207:Cytokines / Q000032:analysis; D015237:Dinoprost / Q000032:analysis; D004804:Eosinophils / Q000502:physiology; D006168:Guinea Pigs; D006854:Hydrocortisone / Q000097:blood; D008168:Lung / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D052247:Nitric Oxide Synthase Type II / Q000032:analysis; D009929:Organ Size; D018384:Oxidative Stress / Q000502:physiology*; D011014:Pneumonia / Q000139:chemically induced / Q000503:physiopathology* / Q000523:psychology; D013315:Stress, Psychological / Q000503:physiopathology*; D013550:Swimming / Q000502:physiology / Q000523:psychology
D000199:Actins; D002395:Catecholamines; D016207:Cytokines; D015237:Dinoprost; D052247:Nitric Oxide Synthase Type II; D006854:Hydrocortisone