Histological and biomechanical changes of rabbit ear cartilage induced by long pulse width 1064 nm Nd: YAG laser / 中华整形外科杂志

ABSTRACT

Objective@#To investigate the histological and biomechanical changes of rabbit ear cartilage induced by long pulse width 1064 nm Nd YAGlaser.@*Methods@#Seven New Zealand rabbits weighing 2.0-2.5 kg, male, 4-6 months old were selected. For a self-control, the right ear was irradiated by laser and the left ear was the normal control group. Each rabbit ear was divided into 3 cm × 1 cm, three 2 cm × 1 cm and 1 cm× 1 cm experimental area. After the experimental area of the laser irradiation group was irradiated by long pulse width 1064 nm Nd YAG laser, Three pieces of 2 cm × 1 cm cartilage in each ear of the experimental rabbits were immediately cut and stained with HE, Sirius red and Masson to observe the histological changes of chondrocytes. The 3 cm × 1 cm and 1 cm× 1 cm cartilage of each rabbit ear was cut for biomechanical examination, and the changes of biomechanical properties such as tension, fracture, elastic modulus and compression of rabbit ear cartilage were observed immediately after the operation.@*Results@#Histological observation showed that the chondrocytes became small, the matrix was stained deeply, the refraction was obvious/evident and the collagen was relatively increased. After being irradiated by long pulse width 1064 nm Nd YAG laser, the peak tensile stress, tensile elastic modulus, tensile fracture load, compressive stress peak, compressive elastic modulus and compressive failure load of rabbit ear cartilage in laser irradiation group were (5.22 ±0.80) MPa, (42.40 ±9.78) MPa, (22.86 ±4.85) N, (16.04 ±5.57) MPa, (28.71 ±13.97) MPa, (1 211.63 ±427.86) N. All of them were smaller than those of the control group[(6.07±0.64) MPa, (48.44±6.30) MPa, (26.94±4.19) N, (25.12±9.10) MPa, (45.30±19.24) MPa, (1 962.83±896.71) N], and the difference was statistically significant (P<0.05).@*Conclusions@#After the operation of long pulse width 1064 nm Nd YAG laser, the stress of rabbit ear cartilage resisting elastic deformation is reduced, the shape is easier to change, and the remodeling effect is more stable.