Fig. 4

Effect of vitamin D deficiency on parenchymal inflammation in air- and CS-exposed mice after 6 and 12 weeks. At the age of 8 weeks, C57Bl/6J vitamin D deficient and control mice were exposed to CS or ambient air for a period of 6 or 12 weeks. a Representative figures of H&E-stained lung sections of each experimental group (200X magnification) after 6 weeks of smoking. Full arrows show the presence of peribronchial lymphocytic inflammation, while dashed arrows show the presence of pigmented macrophages in CS-exposed vitamin D deficient mice. b The diffuse presence of macrophages and the presence of c alveolar and d peribronchial lymphocytic inflammation on histological lung sections was given a semiquantitative score ranging from 0 to 3 by a pathologist in a blinded manner (0 = absent, 0.5 = minimal, 1 = mild, 2 = moderate and 3 = severe). n = 10–12 per group per time point; mean ± SEM; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001