Gfi1-ko/ko mice kept under nonSPF conditions develop osteopenia.

<p><b>(A)</b> Trabecular bone of vertebrae was measured with microCT. Gfi1-ko/ko mice kept under nonSPF conditions developed severe osteopenia as indicated by 60% BV/TV reduction compared to Gfi1-wt/wt mice. Upon SPF breeding Gfi1-ko/ko mice show a 15% reduction in BV/TV. However, SPF+nonSPF conditions induced intermediate osteopenia characterized by approx. 30% BV/TV reduction. Please note Gfi1-ko/ko mice kept at nonSPF conditions develop cortical bone osteopenia in femur. <b>(B)</b> Representative bone sections stained with von Kossa/ Kernechtrot illustrate trabecular bone in vertebrae of mice kept under nonSPF, SPF and SPF+nonSPF conditions. <b>(C)</b> Quantification of bone tissue by histomorphometry revealed reduced BV/TV values in Gfi1-ko/ko vertebrae under nonSPF and SPF+nonSPF conditions compared to controls. Breeding within the SPF environment did not significantly affect bone mass of Gfi1-ko/ko mice. <b>(D)</b> Histomorphometric quantification of the osteoblast covered bone surface (Ob.S/BS) shows reduced but elevated values upon nonSPF and SPF+nonSPF breeding, respectively. SPF breeding did not affect Ob.S/BS between control and mutant mice. <b>(E)</b> Quantification of the osteoclast covered bone surface (Oc.S/BS) revealed diminished but raised values in Gfi1-ko/ko mice upon nonSPF and SPF+nonSPF breeding compared to their corresponding Gfi1-wt/wt controls, respectively. Gfi1-ko/ko mutants grown under SPF conditions showed elevated Oc.S/BS counts compared to Gfi1-wt/wt mice. For better comparability, Gfi1-wt/wt values were set to 1 and Gfi1-ko/ko values were relatively calculated for each breeding condition. Please see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198510#pone.0198510.s008" target="_blank">S2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198510#pone.0198510.s009" target="_blank">S3</a> Tables for absolute values. Error bars represent SD and statistical significance was calculated with t-test, * p ≤ 0.05 and ** p ≤ 0.01.