Severe but not moderate hyperoxia of newborn mice causes an emphysematous lung phenotype in adulthood without persisting oxidative stress and inflammation

Table 2 Lung morphometric parameters of PND60 mice treated with neonatal hyperoxia

Parameter		N		mH		sH
Parameter		Normoxia		moderate Hyperoxia		severe Hyperoxia
Alveoli
alveolar wall thickness	(μm)	12.3	± 2.90	13.9	± 5.35	17.6	± 5.41 ^***
radial alveolar count	(n)	8.70	± 1.96	8.71	± 1.73	7.53	± 1.53 *
Cell number (stained nuclei)
per tissue area ^a	(n∙10²∙mm⁻²)	28.3	± 7.45	27.3	± 6.55	20.5	± 4.88 ^***
per tissue and airspace area ^a	(n∙10²∙mm⁻²)	1.55	± 2.80	1.53	± 2.95	1.41	± 1.96
Airspace size (mean linear intercept)
all airspaces ^a	(μm)	23.2	± 3.53	23.5	± 4.26	26.0	± 4.00 *
small airspaces ^b	(μm)	11.7	± 2.89	12.3	± 3.14	13.2	± 2.18
medium airspaces ^b	(μm)	17.1	± 2.96	17.9	± 3.45	19.5	± 3.21 *
large airspaces ^b	(μm)	26.7	± 4.15	27.3	± 4.86	31.3	± 5.61 ^**

All parameters were analyzed by use of hematoxylin-eosin-stained lung sections (see Additional file 1: Figure S1 for examples each treatment option)
Data are means ± SD (n = 24 each group) with *P ≤ 0.05, ^**P ≤ 0.01 and ^***P ≤ 0.001 vs. N group
^aAreas of airways were omitted in order to get morphometric data of the lung parenchyma
^bSizing according to values of the mean linear intercept for lower quartile, median and upper quartile, respectively

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