Early Effects Of Nasal Obstruction On The Development Of Condylar Cartilage In Rats And Early Intervention Research

PURPOSE: In this study,we investigated the early effects of intermittent nasal obstruction and early intervention on development of condylar cartilage via animal model.METHODS:(1)Thirty two 4-week-old SD rats were randomly divided into two groups,each group contains 16 rats: Group NB: nasal-breathing(control group);Group MB: mouth-breathing.On 4th,8th,12 th,and 16 th day during modeling,condyle specimens was disarticulated for histological analysis;mandibular condylar chondrocyte(MCCs)from animal models were cultured in vitro for chondrogenesis potential analysis.(2)Sixty eight 4-week-old SD rats were randomly divided into four groups,each group contains 16 rats: Group A: nasal-breathing(control group);Group B: 4-day mouth breathing caused by nasal obstruction then return to nasal breathing;Group C: 8-day mouth breathing caused by nasal obstruction then return to nasal breathing;Group D: 16-day mouth breathing caused by nasal obstruction.On 4th,8th,12 th,and 16 th day during modeling,condyle specimens was disarticulated for histological analysis;mandibular condylar chondrocyte(MCCs)from animal models were cultured in vitro for chondrogenesis potential analysis.RESULTS:(1)On 4th,8th,12 th,and 16 th day during modeling,cartilage development of Group MB presented a trend of downwards-shortly upwards-downwards finally compared with Group NB;(2)On 4th,8th,12 th,and 16 th day during modeling,cartilage development of Group B and C showed a trend of downward when performed nasal obstruction and upwards after obstruction removal.CONCLUSIONS: During early phase of intermittent nasal obstruction,condylar cartilage of young rats showed potential of resistance and restoration;early intervention of removing obstruction can accelerate condylar cartilage restoration in a short period.