Effect Of Tensile Stress On The Expression Of Type â…¡ Collagen And Aggrecan In Rat Condyle Chondrocyte

Objective:The condylar cartilage as a major growth center was major functional areas of orthopedic treatment which directs response to the clinical therapy. To study the effect of cyclic tensile stress on condyle chondrocyte main extracellular matrix based on successful construction of in vitro mechanical stimulation models.Methods:Primary cultures of chondrocytes were established from mandibular condyles of2week-old S.D.rats. Chondrocytes phenotype identification was done through morphological features and toluidine blue staining. The cyclic tensile stress was exposed to the third passage condyle chondrocyte for0,1,6,12and24hours respectively by using a Flexcell Strain Unit-5000T(10%surface elongation,6cycles/min). After mechanical loading, total RNA was extracted from the cells harvested from Six-well BioFlex flexible cell Petri Dish, and RT-PCR was performed to quantify mRNA levels for type â…¡ collagen and aggrecan.Results:â‘ Mechanical separation-enzymatic digestion combined method successfully established a rat condylar chondrocytes in vitro culture system.â‘¡RT-PCR showed that: Compared with the control group (Oh group),both type â…¡ collagen and aggrecan mRNA expression were increased after lh loading, but there were no significant differences between loading and control group; after6h cyclic tensile stress, the expression of Col-â…¡ and AGG increased significantly (p<0.05); after12and24h of loading, the expression for these two cartilage-specific matrix proteins reduced remarkably(p<0.05).Conclusion:Mechanical separation-enzymatic digestion combined method can be successfully isolated rat condylar chondrocytes. Cyclical tensile stress stimuli can affect the main condylar cartilage extracellular matrix synthes. Col-â…¡ and AGG can be promoted during early loading, with extended matrix synthesis increased continue, afterwards, further extend the matrix synthesis will be inhibited.