Influence Of Treadmill Exercise On Long Bone In Growing Rats

ObjectiveThis study through the use of different intensities treadmill exercise training on SD rats in growing, observe various intensities on the growth of the tibia length and height, to observe the changes in Board structure; explore the HIF-1? and?collagen in different intensities treadmill exercise on mechanism of effects of rat growth plate.For teenagers of normal bone growth and reasonable arrangement of the training to prevent the exercise intensity is too large and the adolescent skeletal damage is significant.MethodThe experiment selected male SD rats in the growth period(5 weeks old) of 40 as the subject investigated. Using random methods 40 male SD rats were divided into four groups, including two groups: control group and experimental group,experimental group can be divided into a control group, medium intensity treadmill group and high intensity treadmill group, 10 in each group. Treadmill running group for 8 weeks of treadmill training. Executed respectively for all rats injections of tetracycline hydrochloride and calcein. Treadmill exercise group after the completion of training for all groups were drawn to measure the length of the tibia of the rats,measure the height growth plate in rats in each group as well as its growth rate,observation of HIF-1? and?collagen expression in the strength of the growth plate.Result1. Changes of tibial growth(1) the tibial length changes: the length of the tibia value of the blank Group(4.65 ± 0.06) is the minimum,which is showed significant differences(P<0.05) with the control group(5.46 ± 0.07), and presented a very significant difference(P<0.01)with the moderate Group(5.72 ± 0.13) and high intensity groups(5.65 ± 0.10); the length of the tibia value of the control group is less and showed significant differences(P<0.05) with the moderate Group and working groups; the length of the tibia value of the moderate Group is longer than the high intensity group but there was no significant difference between the two group.(2) Between each group under HE staining morphological changes: the layers of cartilage cells of the control group arranged in neat rows, proliferation was significantly columnar arrangement of layers, proportion of hypertrophy and proliferation, and on the proliferation of mast floors before a significant interaction between mast cells; control group relative increase in the number of resting cartilage cells, the total height of the growth plate, proliferation and hypertrophy the height of a five-week gap significantly lower, and you don't see the former hypertrophy layer.Compared to the control group and the control group,intensities treadmill exercise group and high intensity running exercise fat layer of cartilage cells decreased cell edge roughness, both proliferation and the fat layer, you don't see former hypertrophy,proliferation and hypertrophy of distribution than the other two groups are more obvious. The total height of the growth plate, the proliferation of mast height of the layer in the layer relative to the control group also decreased.(3) Changes in the growth plate height: the growth plate height of the blank Group(85.29 ± 11.65), proliferation of layer height(40.477 ± 5.51), mast height(39.760 ± 6.96) are presented a very significant difference(P<0.01) with the control group(50.60±6.99, 27.943±4.44, 20.156±3.12)and moderate-intensity group(36.24 ±5.25, 19.987 ± 3.14, 13.284 ± 2.79) and high intensity group( 30.48±3.74 ?17.568±3.74?10.914±1.53), the growth plate height, proliferation of layer height and mast height of the control group are presented a very significant difference(P<0.01)with the moderate-intensity group and high intensity group, the growth plate height,proliferation of layer height and mast height of the moderate intensity group showed no significant difference with high intensity group.(4) Changes of growth rate: the growth rate of the blank group(202.381±22.979)is presented a very significant difference(P<0.01) with the control group(87.60±8.807) and moderate-intensity group(62.50±8.649)and high intensity group(48.73±10.926), the growth rate of the control group is presented a very significant difference(P<0.01) with the moderate-intensity group and high intensity group, the growth rate of the moderate intensity group showed no significant difference with high intensity group.2. The expression of HIF-1? and?collagen in the growth plate(1) The HIF-1? expression in growth plate: The main expression of HIF-1?expression in proliferating layer and the front mast layer, proliferation was up to, but in the control group and moderate-intensity group and high intensity group, it was able to see the strength of hypertrophic layer exists expression of HIF-1?. In the blank group you can see a lot of obvious HIF-1? expression in the cell nucleus, although it is possible to see some HIF-1? expression in the control group and moderate-intensity group and high intensity group, but is far better than the blank group, and the differences between three groups of smaller, up to the control group. The average optical density of the blank group(0.446±0.031)is showed significant differences(P<0.05) with the control group(0.383±0.031)and it is presented a very significant difference(P<0.01) with the moderate-intensity group(0.383±0.031),but it showed no significant difference with high intensity group(0.463±0.044); the average optical density of the control group is showed no significant difference with the moderate intensity group,but it is presented a very significant difference(P<0.01) with the high intensity group; the moderate intensity group is presented a very significant difference(P<0.01) with the high intensity group.(2) The?collagen expression in growth plate: The main expression of?collagen expression in proliferating layer and the front mast layer, proliferation was up to, but in the control group and moderate-intensity group and high intensity group, it was able to see the strength of hypertrophic layer exists expression of?collagen, the high intensity group was up to. Several sheets of film in the blank group and the control group, you can see a lot of ? collagen, also there are some no, however, the moderate groups and high intensity group with only a very few films can be seen?collagen, most see no expression of ? collagen. The average optical density of collagen ?were no differences among the groups.Conclusion1. Treadmill exercise growing up to promote the growth of rat tibia length, and has nothing to do with the medium and high intensity treadmill exercise.2. Treadmill exercise intensity and high intensity treadmill exercise will suppress growth period of rat tibia growth rate, may be associated with based time single.3. High intensity exercise by HIF-1? expression layer cell secrete ?collagen and differentiation to mast cells inhibit proliferation ability, at the same time make the fat layer mineralization at a slower pace, eventually making growth rate slows down.