Effects Of Cyclic Fluid Pressure On Tissue Engineering Cartilage In Vitro

ObjectiveTo establish a new cyclic fluid pressure culture system and to explore the effects of the cyclic fluid pressure on the construction of tissue engineering cartilage in this system,in vitro.Methods1.Repetendum compressing pump is a piston pump which is pulled by a bolt propeller controlled by a digital unit.The cyclic fluid pressure culture system is composed of repetendum compressing pump and hydrofucosing bioreactor with compensating,preventing overload and automatic perfusing devices.2.Chondrocytes isolated from rabbit articular cartilage were seeded into PLGA scaffolds after expansion in vitro.Three experimental groups were subject to the cyclic pressure with different magnitude(0-50Kpa, 0.1Hz;0-100Kpa,0.1Hz;0-200Kpa,0.1Hz)while the control group was cultured under normal condition.All groups were cultured in the cyclic fluid pressure culture system.After two weeks,the tissue engineering cartilages were harvested and examined macroscopically histologically and immunohistochemically.The quantitation of GAG,collogen typeⅡand DNA of the tissue engineering cartilages was done.3.Chondrocytes isolated from rabbit articular cartilage were seeded into PLGA scaffolds after expansion in vitro.Three experimental groups were subject to the cyclic pressure with different frequencies(0-200Kpa, 0.1Hz;0-200Kpa,0.01Hz;0-200Kpa,1Hz)while the control group was cultured under normal condition.All groups were cultured in the cyclic fluid pressure culture system.After two weeks,the tissue engineering cartilages were harvested and examined macroscopically histologically and immunohistochemically.The quantitation of GAG,collogen typeⅡand DNA of the tissue engineering cartilages was done.Result1.Our cyclic fluid pressure culture system can produce stable cyclic fluid pressure raging from 0 to 350KPa in magnitude and from 0.01Hz to 1Hz in frequency.2.The tissue engineering cartilages of three experimental groups which are under the different magnitude compressure were thicker and produced more extracellular matrix and DNA than the control group's (P＜0.01).What's more,the ones with 0.1Hz 200Kpa cyclic pressure was morphologically the thickest,and produced the much more GAG,typeⅡcollagen and DNA in four groups(P＜0.01).3.The results of the groups under the different frequency compressure are the same as the results of the different magnitude compressure groups(P＜0.01).In these groups,the tissue engineering cartilages with 0.1Hz 200Kpa cyclic pressure was morphologically the thickest,and produced the much more GAG,typeⅡcollagen and DNA in four groups,too(P＜0.01).ConclusionThe cyclic fluid pressure culture system can produce stable cyclic fluid pressure as required.The synthesis of GAG,typeⅡcollagen and DNA was increased by the cyclic pressure.It is better for chondrocytes to proliferate and synthesis extracellular matrix just as GAG and typeⅡcollagen,under the cyclic pressure with suitable magnitude and frequency.