Am. J. Respir. Crit. Care Med., Vol 153, No. 2, 02 1996, 724-730.
Alveolar destruction in guinea pigs chronically exposed to diesel engine exhaust. A light- and electron-microscopic morphometry study
A Nagai, Y Kakuta, Y Ozawa, H Uno, S Yasui, K Konno, A Kata and J Kagawa
First Department of Medicine, Tokyo Women's Medical College, Japan.
Guinea pigs were exposed 16 h a day, 6 d a week, for 6, 12, 18, or 24 mo to
filtered air or diesel-exhaust at low (NO2 = 0.22 +/- 0.03 ppm; SO2 = 0.60
+/- 0.19 ppm; particles = 0.21 +/- 0.07 mg/m3), medium (NO2 = 1.07 +/-
0.09; SO2 = 2.83 +/- 0.73; particles = 1.14 +/- 0.26) or high (NO2 = 2.88
+/- 0.29; SO2 = 6.49 +/- 1.75; particles = 2.94 +/- 0.69) concentrations,
or at a medium concentration without particles (NO2 = 1.01 +/- 0.09; SO2 =
2.66 +/- 0.64; particles = 0.01 +/- 0.01). We quantitated the holes in the
alveolar wall and alveolar size by using scanning electron microscopy
(SEM). After 12 mo of exposure, the ratio of the area of alveolar holes to
that of the alveolar wall, and the number of holes per alveolus, rose as
the concentration and duration of exposure increased. There were no
differences in alveolar size between the study groups. Animals exposed to
the medium concentration of diesel exhaust without particles showed less of
an increase in the development of holes than animals exposed to the same
concentration of diesel exhaust with particles. These findings suggest that
diesel exhaust causes alveolar destruction (alveolar holes) without an
enlargement in alveolar size in a concentration- and duration-dependent
manner. Particulate matter in diesel exhaust may play some role in the
development of these lesions.
