ABSTRACT
Objective:To explore the effects of IGF-1 on cognitive function in REM sleep deprivation model mice and its possible mechanism.Methods:C57BL/6J mice aged 8 weeks were randomly divided into 4 groups with 6 mice in each group.They were Normal control group (CC group), REM sleep deprivation 5d group (SD group), REM sleep deprivation 5d+ Intraperitoneal injection of IGF-1 group (SD+ IGF-1 group), and REM sleep deprivation 5d+ Intraperitoneal injection of PBS group (SD+ PBS group). The Morris water maze was used to test the cognitive function of all mice.The content of IGF-1 in mice hippocampus was detected by Elisa, and the expression level of TNF-α, IL-1β and IL-6 mRNA in mice in hippocampus was determined by RT-qPCR.Western blot was used to detect the protein expression levels of p-GSK3β, GSK3 beta, p-Akt, Akt, Bcl-2 and Caspase-9 in mice hippocampus of each group.Results:The time in the target quadrant and the number of times across the platform of the SD group ((11.87±1.67)s, (12.50±5.54) times, respectively)was lower than that of the CC group((19.40±1.75)s, (22.17±8.21) times, respectively), the difference was statistically significant( t=8.71, 2.26, both P<0.05). The time in the target quadrant and the number of times across the platform of the SD+ IGF-1 group ((18.11±1.12)s, (21.83±10.26) times), which were higher than those in the SD+ PBS group ((10.60±1.36)s, (11.50±3.94) times). The difference was statistically significant( t=8.69, 2.42, both P<0.05). The expression of IGF-1 protein in the hippocampus of SD group ((579.38±55.95) pg/mg) was lower than that of CC group ((729.13±79.46)pg/mg), and the difference was statistically significant ( t=3.83, P<0.05). The expression of IGF1 protein in the hippocampus of SD+ IGF-1 group((665.50±55.21)pg/mg) was significantly higher than that of SD+ PBS group ((563.40±76.33)pg/mg), the difference was statistically significant ( t=2.61, P<0.05). The expression of p-GSK3 beta protein (1.51±0.02) in mice hippocampus of SD group was higher than that of CC group (1.47±0.03), and the expression of p-Akt (0.92±0.04) was lower than that of CC group (1.18±0.05), The difference was statistically significant ( t=3.07, t=10.85, both P<0.05). The expression of Caspase-9 in mice hippocampus of SD group(0.65±0.03)was higher than that of CC group (0.60±0.02). The expression of Bcl-2 in mice hippocampus of SD group (0.93±0.03) was lower than that of CC group (1.00±0.04), and the difference was statistically significant ( t=3.65, 3.98, both P<0.05). The expression of p-Akt and p-GSK3β protein in mice hippocamps of SD+ IGF-1 group( (1.20±0.04), (1.57±0.03)) was increased compared with those of SD+ PBS group ((0.92±0.05), (1.51±0.03)), and the difference was statistically significant ( t=3.98, 11.49, both P<0.05). The expression of Caspase-9 in mice hippocamps of SD+ IGF-1 group (0.60±0.03) was decreased compared with that of SD+ PBS group (0.67±0.02). The expression of Bcl-2 in mice hippocampus of SD+ IGF-1 group (1.00±0.03) was increased compared with SD+ PBS group (0.93±0.02), and the difference was statistically significant ( t=5.19, 3.83, both P<0.05). The expression level of TNF-α, IL-1β, and IL-6 mRNA in mice hippocampus of SD group ((3.36±0.67), (2.00±0.40), (4.63±0.72)) were increased compared with CC group with statistically significant differences ( t=8.58, 6.15, 2.37, all P<0.05). The expression level of TNF-α, IL-1β, and IL-6 mRNA in mice hippocampu of SD+ IGF-1 group ((1.21±0.25), (1.08±0.33), (0.98±0.47)) were lower than those of SD+ PBS group ((3.86±0.79), (2.11±0.30), (4.43±0.67)), with statistically significant differences ( t=7.81, 5.76, 10.39, all P<0.05). Conclusion:The cognitive function of mice decreased after REM sleep deprivation and improved after IGF-1 supplementation, which may be related to the activation of PI3K / Akt signal pathway by IGF-1, thus reducing apoptosis related signal transduction and inflammatory factor expression.
ABSTRACT
@# Objective To test the effect of different flexion angles of knee joint on the myoelectric activity and torque of quadriceps femoris and hamstring muscle when these muscles contracting.MethodsElectromyographic activities and isometric torque measurements were performed on 10 healthy subjects at 30°, 60° and 90° of knee joint flexion.ResultsThe results indicated that the greatest maximal voluntary isometric contracture-torque of quadriceps femoris occurred during knee extension at 60° of knee flexion ( P<0.01). However, no significant relationship of maximal voluntary isometric contracture-electromyography and maximal voluntary isometric contracture-torque of quadriceps femoris were found in 10 subjects. But when knee joint was at 90° flexion, hamstring muscle had a greatest neuro-myoelectric activity.ConclusionThe exercise of maximal voluntary isometric contraction of quadriceps femoris and hamstrings muscles at certain knee joint angle can help to maintain the stability of knee joint.