The role of blood brain barrier in postoperative cognitive dysfunction of elderly mice / 复旦学报（医学版）

Objective To observe the changes of learning and memory ability in aged mice after appendectomy or isoflurane exposure and the permeability of blood brain barrier (BBB) in hippocampus in order to find the reasons for the destruction of BBB damgge.Methods Thirty C57BL mice (18-month) were randomly divided into 3 groups:control group (group C),surgery group (group S) and inhalation group (group Ⅰ).The permeability of BBB in hippocampus was detected with Evans-blue (EB) quantification.The alterations of tight junction protein were measured by occludin and claudin-5 using Western blot on the same day.The changes of two matrix metalloproteinases MMP-2 and MMP-9 were detected.Results Compared with the control group and inhalation group,surgery group had longer escape latencies and less platform crossings,and EB leaked into the hippocampus.The expression of occludin decreased,while the expressions of MMP-2 and MMP-9 increased.Conclusions MMP-2 and MMP-9 may cause the decrease of the expression of tight junction occludin protein,and lead to the destruction of BBB,which resultes in postoperative cognitive dysfunction.

Biomechanical Analysis and Electromygraphy for Sternocleidomastoideus Contraction on Neck Flexion and Extention / 中国康复理论与实践

@#Objective To investigate the effects of bilateral sternocleidomastoideus contraction on neck flexion and extension. Methods The electromyograms (EMG) signals of left sternocleidomastoideus of 24 healthy persons were recorded respectively when neck relaxation and flexion in the supine position, and neck relaxation and extension in the prone position. The biomechanical measurement and analysis were done using anatomical specimens and models. Results The sternocleidomastoideus registered electrical resting potential when neck relaxation in the supine position, and when neck relaxation and extension in the prone position; the motor unit action potential of sternocleidomastoideus raised the type of mixed phase when neck flexion in the supine position. Conclusion The contractions of bilateral sternocleidomastoideus can lead to the head and neck flexion while neck joints are not fixed, and the contractions of bilateral sternocleidomastoideus can lead to the head extension under the state of fixing neck joints below atlanto-occipital.