【Abstract】 Objective To summarize the application and research status of the hip protector (HP) and to discuss the current problems and further research direction. Methods HP related literature in recent years was reviewed and analyzed. Results Biomechanics experiment studies have shown that HP could protect hip joint from fractures caused by falling, however, the protective effect of HP has not shown clinically. Conclusion HP biomechanical experiments show better protective effect, which may be related with the lower impact energy; in clinical application, poor compliance of HP is considered as the main reason of weak protective effect.
Objective To review researches of the role of inhibitorof differentiation 2(Id2) in skeletal muscle regeneration. Methods The latest original literature concerning Id2 and its role in skeletal muscle regeneration was extensively reviewed. Results Id2 could form heterodimers by combining with E protein to prevent myogenic regulatory factors (MRFs) forming heterodimers by combining with E protein, to inhibit the transcription activity of MRFs anddifferentiation of skeletal muscle cell. Conclusion Id2 plays an important role in skeletal muscle regeneration.
Objective To analyze the expression changes of Pax7 and MyoD in satell ite cells of denervated skeletal muscle at the mRNA and protein level, and to explore the pathway concerning with denervation and regeneration of skeletal muscle. Methods Nine male SD rats of 2 months old, weighing 180-200 g were selected. The right gastrocnemius musclewas made denervation model as experimental sides, and the same operation was performed in the left sides as control. The immunofluorescence analysis was done for detecting the protein expressions of Pax7 and MyoD in muscles denervated 3, 7 and 21 days after operation. The RT-PCR analysis was used to explore the mRNA expression of MyoD and Pax7 in extracted tissues from denervated muscles. Results Nine rats survived after operation, with l imited motion of right hind l imbs, and normal motion of left l imbs. The result of immunofluorescence with the polyclonal antibody against MyoD and the monoclonal antibody against Pax7 showed that the number of MyoD positive cells in prolonged denervated muscles (experimental sides) increased gradually, and reached the peak 21 days after denervation, there was significant difference compared with that of control sides (P lt; 0.05). However, the total number of Pax7 positive cells decreased with the prolongation of denervation, the expression of Pax7 was b only at 3 days, then decreased gradually, and there was no positive cells in denervated muscles of 21 days. There were significant differences in Pax7 positive cells between experimental sides and control sides at 3 and 7 days (P lt; 0.05). The results of immunostaining showed that MyoD mRNA levels increased , and reached the peak at 21 days of denervation, there was significant difference compared with that of control sides (P lt; 0.05). Whereas, Pax7 mRNA expressed only in control, denervated muscles of 3 and 7 days, and its expression level decreased gradually. Conclusion One possible reason of the depletion of satell ite cell pool in prolonged denervated muscle is the down-regulation of Pax7.