Fig. 1
Rib defect surgery and timeline. After the rat had been anesthetized, intubation and mechanical ventilation were established to maintain positive pleural pressure. The animal was then placed on its side and shaved (a). A 2-cm-long longitudinal cut was made along the mid-axillary line (b), and the latissimus dorsi muscle was removed by blunt dissection (c) until the rib cage was fully exposed (d). A 5-mm-long segment was removed from both the fifth (e) and sixth (f) ribs. The ribs were stitched separately, followed by suturing of the muscular layer (g) and skin (h). The animals were divided into four groups: (1) a negative control group; (2) the hMSC-only group, in which rats received five injections of 2 × 106 hMSCs every 3–4 days beginning on the 3rd day after surgery; (3) the PTH-only group, in which rats received daily injections of 4 μg/kg PTH for 17 days, beginning at the third day after surgery; and (4) the hMSC + PTH group, in which rats received both treatments. The animals were scanned by μCT biweekly until they were sacrificed 8 weeks after surgery (i). PTH parathyroid hormone, μCT micro-computed tomography