| ObjectiveTo investigate the variation of femoral biomechanics in type1diabetic rats and characteristics of femoral biomechanical in diabetic osteoporosis, so as to explore the reasonable intervention time of prevention and treatment for diabetic osteoporosis, which might guide clinical drug use.Methods1. Grouping and modeling96six-to-eight-week-old female Wistar rats were randomly invided into two groups: diabetes model group (group D, n=48) and control group (group C, n=48). Group D were pre-treated with a single intraperitoneal dose of60mg/kg STZ to induce experimental diabetes.Fasting glucose of72hour post-injection over16.7mmol/L was taken as experimental criterion. According to the sampling time (1w,2w,3w,4w,5w,8w,12w,16w), group D and group C were subdivided into Clw, C2w, C3w, C4w, C5w, C8w, C12w, C16w (n=6, respectively) and Dlw, D3w, D4w D2w, D5w, D8w, D12w, D16w,(n=6, respectively).2. Specimens collection and preservationAfter weighted, rats in group C and group D were intraperitoneally injected with ketamine(100mg/kg) for general anesthesia. Take the left femur with normal saline soaked gauze packaged to preserve in the-20℃.3.Determination of biomechanical indexThe three point bending test of femur were performed in room temperature. The specimen is the whole length of femur, loading point is located in the middle of the femoral, the spacing of the two points is20mm and the loading speed is2mm/min, load-deformation curve was recorded. The maximum load, elastic load, the elastic modulus and energy absorption index were obtained.Results1.Changes of rats’body weight1.1intrablock analysis:weight of rats in group D was lower than that in group C in all points,but only the weight of rats in D8w、D12w、D16w decreased significantly (P<0.05).1.2intrablock analysis:(1) Weight of rats in group C gradually increased from the1st week to the16th week, the peak is at the16th week, which have statistically significant difference (P<0.05).(2) The overall trend of weight in group D is that increased before the5th week,then decreased in the8th week and in the12th and16th week make another increase.the peak is in the16th week.Difference has statistics significance (P<0.05).2.Changes of biomechanical index2.1intergroup analysis:the maximum load, elastic load, elastic modulus and energy absorption of rats in group D in the8th,12th and16th week are lower than that in group C, which have statistically significant difference (P<0.05).2.2intrablock analysis:2.21Maximum load:(1)the maximum load of rats in group C is straight increased from the1st week to the16th week,the peak is in the16th week.Difference has statistics significance (P0.05).(2)the overall trend of the maximum load in group D is that increased before the5th week,then decreased in the8th and12th week and make another increase in the16th week.But there is no statistical significance in group D. 2.22elastic load:(1)the elastic load of rats in group C is continuously increased from the1st week to the16th week,the peak is in the16th week.Difference has statistics significance (P<0.05).(2)the overall trend of the elastic load in group D is that increased before the5th week,then decreased in the8th and12th week and make another increase in the16th week.But there is no statistical significance in group D(P<0.05).2.23elastic modulus:(1)the elastic modulus of rats in group C is straight increased from the1st week to the16th week,the peak is in the16th week.Difference has statistics significance (P <0.05).(2)the overall trend of the elastic modulus in group D is that increased before the5th week,then decreased in the8th and12th week and make another increase in the16th week.The peak is in the5th week.①Compared to D1w,D4w、D5w increased significantly (P<0.05);②Compared to D5w,D2w、D3w、D8w、D12w decreased significantly (P<0.05);2.24energy absorption:(1)the energy absorption of rats in group C is straight increased from the1st week to the16th week,the peak is in the16th week.Difference has statistics significance (P<0.05).(2)the overall trend of the elastic load in group D is that increased before the5th week,then decreased in the8th and12th week and make another increase in the16th week.The peak is in the5th week.①Compared to D1w,D4w、D5w、D8w increased significantly (P<0.05);②Compared to D2w,D5w、D8w increased significantly (P<0.05);③Compared to D5w,D3w、D12w、D16w decreased significantly (P<0.05); ④Compared to D8w,D12w、D16w decreased significantly (P<0.05);ConclusionType1diabetes can reduce the stiffness and flexibility of skeleton significantly, leading to osteopenia and osteoporosis.With the progress of diabetes,the biomechanics index began to decrease after the5th week of diabetic onset. The femoral biomechanics data of diabetes model rats is lower than that of the control group obviously in the8th and12th week. |
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