Figure 2

Establishment of the BLM-mediated acute lung injury model, and improved survival, reduced expression of IGF1R as well as changes in mRNA expression of IGF system genes in IGF1R-deficient mice. (a) Tamoxifen (TMX) was administered daily for five consecutive days to four-week-old UBC-CreERT2; Igf1r ^fl/fl (CreERT2) mice to induce a postnatal Igf1r gene conditional deletion as previously described using Igf1r ^fl/fl mice as experimental controls²³. Six-week-old mice were intra-tracheally instilled with 2.5 µl/g BLM (2 U/ml) or saline using a ketamine-xylazine anesthetic combination. Cellular and molecular analyses were assessed on day (D) 3, based on survival curves. (b) Survival rates after BLM challenge determined over a follow-up period of 21 days in UBC-CreERT2; Igf1r ^fl/fl (CreERT2) (n = 24) and Igf1r ^fl/fl mice (n = 30). Data are expressed as the percentage of mice alive at each time point. (c) Igf1r mRNA expression levels, (d) representative Western blots for IGF1R and graphical representation of densitometric measurements of band intensities (percentage) normalized to beta-Actin levels, and (e) mRNA expression of IGF system related genes (Igf1, Igfbp3, Igfbp5, Insr and Foxo1) in lungs of UBC-CreERT2; Igf1r ^fl/fl (CreERT2) vs. Igf1r ^fl/fl mice at D3 post-intratracheal instillation. Numbers within graphic bars indicate the number of mice analyzed and data are expressed as mean ± SEM. *p < 0.05; **p < 0.01 (Mann-Whitney U test). BLM, bleomycin.