Figure 6

Distribution of lipoprotein lipase mRNA and protein in the perinatal mouse lung. Mouse tissue sections are from saccular stage (A, B, GD 19.5; C, D, G, H, PN 0; I, PN 3; E, F, J, K, PN 5) or alveolar stage (L, M, PN 10). In situ hybridization (above the yellow line) (A to F) was performed with LPL anti-sense (A, C, E, F) and sense (B, D) probes. The major site of LPL mRNA synthesis (positive signal, blue) changed at birth (compare A and C). Positive signals were found in the alveolar wall and possibly in macrophages on PN 5. Immunohistochemistry (below the yellow line) (G-M) was performed using an anti-LPL polyclonal antibody (G to K, M) or goat IgG as negative control (L). Positive signals (red) were found in capillaries in all the analyzed developmental times, in respiratory bronchioles from GD 19.5 to PN 3 (J, K and data not shown), and in macrophages on PN 5 and PN 10 (M and data not shown). Scale bars, 50 μm (A to E, G, L) or 20 μm (F, H to K, M). BV, blood vessel; C, capillary; D, distal epithelium; MA, macrophage; P, proximal epithelium; RB, respiratory bronchiole; V, vein.