Preliminary study on microdissection needle-assisted ear cartilage reshaping in vivo rabbit models / 中国修复重建外科杂志

ABSTRACT

Objective: To preliminarily investigate morghological changes of rabbits reshaping ear cartilage assisted by microdissection needle and explore feasibility of new therapy for ear deformity. Methods: The bilateral ears of 5 male New Zealand rabbits (aged, 5-6 months) were fixed maintaining the curvature and randomly divided into 2 groups (5 ears in each group). The ears were stimulated by microdissection needle in experimental group and were not treated with stimulation in control group. The skin reaction in the experimental group was observed immediately and at 4 weeks after stimulation. Then, the fixtures were removed at 4 weeks, and the shapes of the ears were observed. The cartilages were harvested from the ears to examined morphological changes after HE staining, and measured the chondrocyte layer thickness. Results: All rabbits survived until the end of the experiment. The skin has healed completely after 4 weeks in experimental group. After removing fixtures, the ears in the two groups all maintained certain forms momentarily; while 24 hours later, the ears in the control group mostly recovered original form, and the ears in the experimental group still maintained certain molding form until 8 weeks. HE staining showed there were smooth cartilage and uniform distribution of cells in the control group; the matrix staining was basically consistent; and the skin was normal appearance with epidermis, dermis, and cartilage of normal aspect. But the proliferation of chondrocyte with more layers of cells were observed in the experimental group. In addition, there were degeneration and injury of cartilage cells and connective tissue with necrotic cells and inflammatory cells at needle insertion sites. The chondrocyte layer thickness was (385.714±2.027) μm in the control group and (1 594.732±1.872) μm in the experimental group, there was significant difference between the two groups ( t=-759.059, P=0.000). Conclusion: Rabbit ear cartilage can be effectively reshaped by microdissection needle. Proliferation of chondrocyte and changes in matrix can be found during the reshaping process.