[Effects of conventional mechanical ventilation with low tidal volume on the expression of growth factors and inflammatory mediators in developing porcine lungs].
OBJECTIVE
To study the effects of conventional mechanical ventilation (CMV) with low tidal volume on developmental porcine lungs by examining the expression of growth factors and inflammatory mediators.


METHODS
Twelve preterm piglets born at 99 days of gestational age, 12 term neonatal piglets and 11 young piglets (4-5-weeks old) were randomly placed on CMV or were not ventilated (control group). The ventilator settings were adjusted to provide a tidal volume of 6-8 mL/kg in order to maintain a normal blood-gas value. After 6 hrs (preterm piglets) or 24 hrs (neonatal and young piglets) of mechanical ventilation, the mRNA expression of growth factors PDGF-B, IGF-I, KGF, HGF, VEGF and TGF-beta1 and proinflammatory cytokines IL-1beta, IL-6, IL-8 and TNF-alpha in the lung tissue was measured using RT-PCR. Growth factor protein expression was measured with immunohistochemistry.


RESULTS
In preterm piglets, the CMV group had increased mRNA expression of PDGF-B (5.11+/-0.10 vs 4.88+/-0.01), IL-1beta (4.95+/-0.27 vs 4.08+/-0.37), IL-6 (4.76+/-0.27 vs 4.00+/-0.28) and IL-8 (5.31+/-0.57 vs 4.15+/-0.46), but decreased IGF-I mRNA expression (3.54+/-0.13 vs 3.80+/-0.11) compared with those in the control group (P<0.05 or 0.01). In term neonatal piglets and young piglets, there were no significant differences in the mRNA expression of growth factors and proinflammatory cytokines between the CMV and control groups.


CONCLUSIONS
CMV caused inflammatory injury in immature lungs by increasing the expression of proinflammatory cytokines and PDGF-B and decreasing IGF-I expression. However, CMV had no effects on pulmonary expression of growth factors and inflammatory mediators in term neonatal piglets and young piglets.
Liu
Hai-Pei
HP
Department of Pediatrics, Children's Hospital of Fudan University, Shanghai 200032, China.
Qian
Li-Ling
LL
Wang
Wei
W
Zhu
Lie-Wei
LW
Sun
Bo
B
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D007150:Immunohistochemistry; D018836:Inflammation Mediators / Q000032:analysis*; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis* / Q000235:genetics; D008168:Lung / Q000378:metabolism*; D009195:Peroxidase / Q000032:analysis; D010743:Phospholipids / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012121:Respiration, Artificial; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D013990:Tidal Volume; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis / Q000235:genetics
D018836:Inflammation Mediators; D036341:Intercellular Signaling Peptides and Proteins; D010743:Phospholipids; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D009195:Peroxidase