Fig. 4

Soluble elastin in lung tissue homogenate of control animals and animals treated with a single instillation of gastric fluid and studied at 4, 12 and 24 h and at day 4 after instillation, as determined by Western blotting. a The immunoblot shows that the control sample exhibits a single band of soluble elastin with a molecular weight of 70 kDa, likely corresponding to tropoelastin. In samples from treated animals, this band is accompanied by small molecular weight bands in the 35–50 kDa range. The 70 kDa band density increases at 4 h and shows a slight progressive reduction thereafter. Band densities in the 35-50 kDa range are largely increased at 4 h, exhibit a further increase at 12 and 24 h and are significantly smaller at day 4. β-tubulin immunoblot shows equal protein loading. b Densitometric analysis of the 70 kDa Western blot band (n = 6) normalized to beta-tubulin and expressed as times over control. After a significant increase in band density at 4 h, a progressive reduction to reach control level at day 4 is seen. Data are presented as median values, interquartile range and range. **: p < 0.01; *: p < 0.05 with respect to controls and day 4. c Densitometric analysis of the 35–50 kDa Western blot bands corresponding to elastin-degradation fragments (n = 6) normalized to beta-tubulin and expressed as times over control. These band densities increase significantly at 4 h, remain elevated at 12 and 24 h and decrease without reaching control levels at day 4. Data are presented as median values, interquartile range and range. **: p < 0.01; ***:p < 0.001 with respect to controls. h: hours, d: days