ObjectiveTo explore the effect of the expanded capsule on the growth of autogenous costal cartilage. MethodsSixteen New Zealand white rabbits at the age of 3 months (weighing, 2.2-2.5 kg; male or female) were selected and four 15 mL tissue expanders were implanted on the back symmetrically. After 1 month, the expanded capsule formed, the tissue expanders were removed; the capsule of the left side was removed (experimental group), and the capsule of the right side was reserved (control group); meanwhile, the right 7th and 8th costal cartilage without the perichondrium was divided into segments and placed into the capsule of 2 groups symmetrically. At 4 and 8 weeks after transplantation, the cartilage was harvested for the general, weighing, and histological observations. ResultsOne rabbit died during the experiment, and the other 15 rabbits survived. The differences of cartilage weight between before and after transplantation showed more obvious increase in the experimental group[(0.003 4±0.002 7) g and (0.005 8±0.001 4) g] than those in the control group[(-0.000 3±0.001 9) g and (-0.003 9±0.005 3) g] at 4 and 8 weeks, showing significant differences between 2 gouprs (t=4.331, P=0.029; t=6.688, P=0.008). The change of cartilage weight at 8 weeks was significantly higher than that at 4 weeks in the experimental group (t=-3.098, P=0.001); but the change of cartilage weight at 8 weeks was significantly lower than that at 4 weeks in the control group (t=2.491, P=0.009). The histological observation showed that the activity of the cartilage was enhanced in 2 groups at 4 and 8 weeks when compared with normal cartilage, and more obvious change was observed in the experimental group than in the control group. And the acellular area was seen in the cartilage at 8 weeks in the control group. The Masson staining results showed that the color was deeper in the experimental group than in the control group. ConclusionThe removal of the expanded capsule during operation is beneficial to the growth of autogenous costal cartilage. The results can provide corresponding experimental guidance for the clinical problems.