The expression of nerve growth factor in mice lung following low-level toluene exposure.
To clarify the effect of indoor air pollutants on nerve growth factor (NGF) production in lung, male C3H/HeN mice were exposed to filtered air (control) or toluene at levels of 0.9 ppm, 9 ppm, or 90 ppm for 30 min via nose-only inhalation on days 0, 1, 2, 7, 14, 21, 28, 35, 42, 49 and 56. As an allergic mouse model, some mice (n=24) were immunized with ovalbumin. Lungs from each mouse were collected to determine NGF and related receptor expressions using real-time reverse transcription polymerase chain reaction (RT-PCR) analysis. NGF and TrkA mRNAs were increased in the lungs of the immunized mice following exposure to 9 ppm toluene (n=6) (P<0.05 ppm vs. 0 ppm). Remarkably increased NGF-positive bronchiolus and alveolar epithelium cells were observed in 9 ppm toluene-exposed, immunized mice. To determine NGF mediating signaling, we also examined mRNA expression of neurotrophin receptor p75 (p75(NTR)) and oxidative stress marker, heme oxygenase (HO)-1 in the lung. There is no difference in the expressions of p75(NTR) and HO-1 between toluene-exposed and control mice. The expression of CCL2 and CCL3 mRNAs was significantly elevated in 9 ppm toluene-exposed, immunized mice. These findings suggest that the exposure with volatile organic compounds enhanced NGF expression and airway inflammation stronger in allergic individuals than in healthy individuals.
Fujimaki
Hidekazu
H
National Institute for Environmental Studies, Tsukuba, Ibaraki, 305-8506, Japan. fujimaki@nies.go.jp
Tin-Tin-Win-Shwe
Yamamoto
Shoji
S
Nakajima
Daisuke
D
Goto
Sumio
S
D000281:Administration, Intranasal; D000818:Animals; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000235:genetics; D054407:Chemokine CCL4 / Q000096:biosynthesis / Q000235:genetics; D051547:Heme Oxygenase-1 / Q000096:biosynthesis / Q000235:genetics; D007115:Immunization Schedule; D007150:Immunohistochemistry; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D020932:Nerve Growth Factor / Q000096:biosynthesis* / Q000235:genetics; D010047:Ovalbumin / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020800:Receptor, Nerve Growth Factor / Q000096:biosynthesis / Q000235:genetics; D020917:Receptor, trkA / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012997:Solvents / Q000633:toxicity*; D014050:Toluene / Q000633:toxicity*
D018932:Chemokine CCL2; D054407:Chemokine CCL4; D012333:RNA, Messenger; D020800:Receptor, Nerve Growth Factor; D012997:Solvents; D014050:Toluene; D010047:Ovalbumin; D020932:Nerve Growth Factor; D051547:Heme Oxygenase-1; D020917:Receptor, trkA