Figure 4: Measuring the impact of MDSPC transplantation on the lifespan and healthspan of progeroid mice.

(a) 2–4×10⁵ MDSPCs per gram body weight were injected into the peritoneal cavity of 17-day-old Ercc1^−/− mice and lifespan measured. The median lifespan of Ercc1^−/− mice is 21 days; the maximum is 28 days²⁹. The lifespan of Ercc1^−/− mice injected with two independent MDSPC populations isolated from young WT mice were compared with Ercc1^−/− mice injected with vehicle only (PBS), an equivalent number of WT MEFs, or MDSPCs isolated from old WT or progeroid Ercc1^−/− mice. Reported is the average lifespan from 4–10 mice injected per treatment group. Error bars indicate s.e.m. *P<0.05, Dunn's test comparing the WT groups with all other treatment groups. A summary of the cell lines injected and number of animals transplanted can be found in Supplementary Table S3. (b) 2–4 ×10⁵ MDSPCs per gram body weight were injected into the peritoneal cavity of 7-wk-old Ercc1^−/Δ mice and again at 13 wks of age. The age at onset of the characteristic, spontaneous, ageing-related symptoms seen in Ercc1^−/Δ mice was measured (MDSPC-treated mice, black diamonds) and compared with mice injected with vehicle only (PBS; grey squares). Reported is the average age at onset of each progeroid symptom in wks ±s.d. (n=8 mice per treatment group). The ageing score is calculated as the fraction of symptoms that were delayed in a single Ercc1^−/Δ mice injected with young WT-MDSPCs compared with an age- and sex-matched mouse (usually a littermate) injected with PBS (Supplementary Methods). The black bars denote the average ageing score for each group (***P<0.0008, Student's t-test).