In vivo efficacy of 3D-printed elastin-gelatin-hyaluronic acid scaffolds for regeneration of nasal septal cartilage defects

Abstract

Nasal septal cartilage perforations occur due to the different pathologies. Limited healing ability of cartilage results in remaining defects and further complications. This study sought to assess the efficacy of elastin-gelatin-hyaluronic acid (EGH) scaffolds for regeneration of nasal septal cartilage defects in rabbits. Defects (4 × 7 mm) were created in the nasal septal cartilage of 24 New Zealand rabbits. They were randomly divided into four groups: Group 1 was the control group with no further intervention, Group 2 received EGH scaffolds implanted in the defects, Group 3 received EGH scaffolds seeded with autologous auricular chondrocytes implanted in the defects, and Group 4 received EGH scaffolds seeded with homologous auricular chondrocytes implanted in the defects. After a 4-month healing period, computed tomography (CT) and magnetic resonance imaging (MRI) scans were obtained from the nasal septal cartilage, followed by histological evaluations of new tissue formation. Maximum regeneration occurred in Group 2, according to CT, and Group 3, according to both T1 and T2 images with 7.68 ± 1.36, 5.44 ± 2.41, and 8.72 ± 3.02 mm² defect area respectively after healing. The difference in the defect size was statistically significant after healing between the experimental groups. Group 3 showed significantly greater regeneration according to CT scans and T1 and T2 images. The neocartilage formed over the underlying old cartilage with no distinct margin in histological evaluation. The EGH scaffolds have the capability of regeneration of nasal cartilage defects and are able to integrate with the existing cartilage; yet, they present the best results when pre-seeded with autologous chondrocytes.

Keywords: cartilage; nasal septum; regeneration; tissue scaffolds.

FIGURE 1

Auricular chondrocytes were harvested and cultured. A piece of cartilage of the contralateral part of the rabbit's ear was excised (a), chondrocytes were isolated (b) and cultured. (c) The chondrocytes at the first stage of transfer to the culture flask and (d) the proliferated chondrocytes after 7 days

FIGURE 2

Seeded scaffolds with chondrocytes at ×4 (a) and ×10 (b) magnifications

FIGURE 3

Surgical procedure to create defect in the nasal septal cartilage and scaffold implantation. Subperiosteal flap exposed the nasal bones (a), a bony window provided access to the nasal septal cartilage (b) and after creating a defect and replacing the extracted piece of cartilage (on the left) with the scaffold (on the right) (d), the flaps were tightly sutured (c)

FIGURE 4

In vitro characterization of the scaffold (a) The 3D-printed EGH scaffolds. (b) 3D Laser microscope images of scaffold. (c) The SEM images of the BM-MSCs cultured on the 3D-printed EGH scaffold 1 days after culturing in basal media. (d) Viability % of BM-MSCs after 1 and 7 days of culturing in basal medium on 3D-printed EGH scaffolds, and plate, as a control group

FIGURE 5

CT scans in the sagittal (a), axial (b), and coronal (c) sections. MRI T1 scans in the sagittal (d), axial (e), and coronal (f) planes. MRI T2 scans in the sagittal (g), axial (h), and coronal (i) planes. The defects are determined by star

FIGURE 6

Closest tissue to the borders of the defect; the dashed lines indicate the location of section for histological assessment (a), neocartilage formation (arrows) in an EGH scaffold specimen (b), granulation tissue formation (brackets) in an EGH plus homologous cell specimen (c), bone formation (brackets) in an EGH plus homologous cell specimen (d), and neocartilage formation (arrows) in an EGH plus autologous cell specimen (e)