Retinoic acid enhances lung growth after pneumonectomy.
BACKGROUND
We sought to identify the role of retinoic acid (RA) upon lung growth. RA has a role in perinatal lung development, and we hypothesized that exogenous RA would enhance postpneumonectomy compensatory lung growth.


METHODS
Utilizing the postpneumonectomy rat model, we studied the impact of RA upon contralateral lung growth. Adult Sprague-Dawley rats were divided into three groups. Group S underwent a sham left thoracotomy, group P underwent left pneumonectomy, and group R underwent left pneumonectomy with administration of exogenous RA (0.5 microg/g/day intraperitoneally). We then quantitated right lung growth after 10 and 21 days. Lung weight and volume were expressed as a ratio to the final body weight (lung weight and volume indices, LWI and LVI). Epidermal growth factor receptor (EGFR) expression was quantitated using Western blot analysis. Cellular proliferation index (CPI) was determined using BrdU immunostaining.


RESULTS
LWI, LVI, CPI, and EGFR expression at 21 days were significantly higher in group R versus S and P. At the 10-day interval, both LWI and LVI were significantly higher in group R versus S and P.


CONCLUSIONS
RA administration markedly enhances lung growth after pneumonectomy, as evidenced by increases in LWI, LVI, and CPI. Upregulation of EGFR expression was associated with these effects.
Kaza
A K
AK
Department of Surgery, University of Virginia Health System, Charlottesville 22908-1359, USA.
Kron
I L
IL
Kern
J A
JA
Long
S M
SM
Fiser
S M
SM
Nguyen
R P
RP
Tribble
C G
CG
Laubach
V E
VE
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D066246:ErbB Receptors / Q000187:drug effects; D007274:Injections, Intraperitoneal; D008168:Lung / Q000187:drug effects*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011013:Pneumonectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000187:drug effects*; D014212:Tretinoin / Q000494:pharmacology*
D014212:Tretinoin; D066246:ErbB Receptors