Expression Of Collagen Ⅱ And Related Factors In Rat Articular Cartilage Of Knee Joint In Response To Strenuous Running Exercise Of Various Gradient

Object:To study expression of collagen II and related factors in rat articular cartilage of knee joint in response to strenuous running exercise of various gradient.Method:At the age of 16 weeks,18 male wistar rats (300-330g) which were divided to 3 parts started running on a treadmill at 3 kinds of gradient(-20°,0°,+20°). Thereafter, the rats were trained for 45 days continuously. The rats ran 1.0km/d at the speed of 1.0km/h.6 matched male rats served as controls. Their weights were recorded every week. Total RNA was extracted from articular cartilage of knee join, and mRNA levels for collagen II, TNF-a, IL-1β,MMP-3 were measured by real time rt-PCR.Result:1. The weights curve of rats running on a treatmill looked like a "U" with the change of time. AT the forth week, the weights of running rats were the lowest.2. Relative collagen II and aggrecan mRNA levels in rat articular cartilage of running groups were lower than that of free-running group (P＜0.01). Relative collagen II mRNA level of +20°running group was lower than that of-20°running group (P<0.05). Relative aggrecan mRNA levels in rat articular cartilage of+20°running group and 0°running group were lower than that of-20°running group(P<0.05), and there was no difference between+20°running group and 0°running group.3. Relative TNF-a, IL-1βand MMP-3 mRNA levels in rat articular cartilage of running groups were higher than that of free-running group (P<0.05). Relative TNF-a mRNA level in rat articular cartilage of+20°running group was higher than that of 0°running group and-20°running group(P<0.01). No difference of relative IL-1βmRNA level was found among-20°running group,0°running group and+20°running group. Relative MMP-3 mRNA level in rat articular cartilage of+20°running group was higher than that of 0°running group and-20°running group(P<0.01).Conclusion:Strenuous running induced conspicuous decrease of collagenⅡand aggrecan mRNA level in the articular cartilage, and marked increase of TNF-a, IL-1βand MMP-3 mRNA, especially in the articular cartilage of+20°running group. It may indicate that strenuous running with an up-gradient was much easier to damage articular cartilage of knee joint.