OBJECTIVETo study the effect of exercises of different intensities on rat skeletal muscle cell apoptosis.

METHODSRat models of exhaustive exercise-induced skeletal muscle injury was established using tread mill exercises at different speeds, and the skeletal muscle cell apoptosis was detected using propidium iodide (PI) staining and flow cytometry.

RESULTNo obvious gastrocnemius cell apoptosis was observed in rats with normal exercise (P>0.05), but the cell apoptosis index was statistically significant in moderate and exhaustive exercise groups (P<0.05), reaching the highest level in exhaustive exercise group after exercising. The gastrocnemius cell apoptosis index increased obviously on days 1 and 3 of exercise, and stabilized in moderate and exhaustive exercise groups.

CONCLUSIONExercises can evoke cell apoptosis and accelerate apoptotic cell clearance, and the imbalance between the two events during exercises may contribute to skeletal muscle injury.

Animals ; Apoptosis ; physiology ; Flow Cytometry ; Male ; Muscle, Skeletal ; cytology ; physiopathology ; Physical Conditioning, Animal ; physiology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Time Factors

BACKGROUND: At present, the treatment methods for intertrochanteric fracture of the femur in the aged are in two ways: Intramedullary fixation and extramedullary fixation. The advantages of intramedullary fixation with simple operation, small trauma and few complications have become the gold standard for the treatment of intertrochanteric fracture in the femur in the aged. OBJECTIVE: To explore the clinical curative effects of three internal fixation methods: dynamic hip screw, proximal femoral nail antirotation, and intramedullary nail InterTan in the treatment of intertrochanteric fractures of the femur in the aged. METHODS: A retrospective analysis of 120 cases of intertrochanteric fractures from January 2010 to January 2016 was performed. The patients were randomly divided into dynamic hip screw group (n=40), proximal femoral nail antirotation group (n=60) and InterTan group (n=20). The operative time, intraoperative blood loss, incision length, hospitalization time, postoperative weight-bearing time, fracture healing time, Harris score, and intraoperative and postoperative complications were recorded and compared among the three groups. RESULTS AND CONCLUSION: (1) Operative time, intraoperative blood loss, and incision length were significantly better in the InterTan group and proximal femoral nail antirotation group than in the dynamic hip screw group (P < 0.05). Above indexes were not significantly different between InterTan and proximal femoral nail antirotation groups (P > 0.05). (2) Postoperative weight-bearing time, fracture healing time, and Harris score one month after operation were significantly better in the InterTan group than in the proximal femoral nail antirotation and dynamic hip screw groups; above indexes were better in the proximal femoral nail antirotation group than in the dynamic hip screw group (P < 0.05). (3) Hospitalization time and Harris score at 6 and 12 months after operation were not significantly different among the three groups (P > 0.05). (4) The incidence rate of intraoperative and postoperative complications was significantly lower in the InterTan group and proximal femoral nail antirotation group than in the dynamic hip screw group (P < 0.05). (5) In summary, compared with dynamic hip screw system, proximal femoral nail antirotation and InterTan system are characterized by small trauma, simple operation, quick recovery, and fewer complications, and show good clinical therapy in the treatment of intertrochanteric fracture. Compared with proximal femoral nail antirotation system, InterTan system shows better fracture reduction and stability, shorter healing time, and better biomechanical advantages.