A Preliminary Study On The Effects Of Diet And Menstrual Cycle On Vascular Reactivity Of Skeletal Muscle

Part ?A preliminary study on the effects of diet on vascular reactivity of skeletal musclePurpose:To investigate the vascular reactivity of calf muscle in the fasting and satiety state using blood oxygen level dependent(BOLD)magnetic resonance imaging.Methods:Ten healthy men(age,25~33years.mean age,27.4 years)underwent muscle BOLD MR imaging of the right calf in a cuff-compression model.The duration of the model was 160 s in resting phase,352 s in ischemic phase and 352 s in reactive hyperemia phase.The 3D-T1 WI images and the BOLD MR images of the upper calf muscle were performed by using the 3.0Tesla magnetic resonance scanner(Verio,Siemens,Erlangen,Germany).The turbo fast low angled shot squence was used to produce 3D-T1 WI images.The single-shot gradient echo echo-planar sequence was used to produce the BOLD imaging.Preprocessing and analysis of BOLD MR data was carried out using DPARSFA v2.3,RESTv1.9 based on Matlab 2010 a and MRIcro N.Then the data is normalized by the following steps.At first,to calculate the average of the original signal intensity in the rest period 160s(recorded as SImean),and then the original signal intensity of the whole time series(recorded as SItotal)devided by the average of the riginal signal intensity of the resting phase,ie SItotal/SImean×100%.We measured the variables of soleus,tibialis anterior muscle,gastrocnemius muscle of the T2* normalized time signal curve in the fasting and satiety condition respectively,which were the signal intensity changes from the cuff inflation to the end of the ischemic period(?SI1),the time that the signal declines to the minimum value from the cuff inflation(Tmin),time to peak(TTP)and the signal changes from the cuff deflation to T2* maximum value(?SI2).Paired-samples t test was used toanalysis the above variables.Result:The result of the Paired-samples t test shows that ?SI1 of the soleus muscle have significant difference between the fasting and satiety condition(p<0.05).The ?SI1 of soleus muscle in the fasting state(30.5±13.3%)was significantly higher than that of the satiety condition(22.8±15.3%).Tmin,?SI2 and TTP of the soleus muscle have no significant difference.?SI1 of the tibialis anterior muscle have significant difference between the fasting and satiety condition(p<0.05).The ?SI1 of the tibialis anterior muscle in the fasting state(15.0±5.5%)was significantly higher than that of the satiety condition(9.7 ±5.3%).Tmin,?SI2 and TTP of tibialis anterior muscle have no significant difference.?SI1,Tmin,?SI2 and TTP of gastrocnemius muscle have no significant difference between the fasting and satiety condition.Conclusion:The vascular reactivity of calf muscle is related with the meal in the ischemic phase of BOLD MR imaging of calf muscle in a cuff-compression model.The ?SI1 of soleus muscle and tibialis anterior muscle in the fasting condition was significantly higher than that of satiety condition.The vascular reactivity of calf muscle is not affected by meals during postocclusive reactive hyperemia.Part ? A preliminary study on the effects of menstrual cycle on vascular reactivity of skeletal musclePurpose:To investigate changes of vascular reactivity in calf muscle of childbearing age women during menstrual cycle using blood oxygen level dependent(BOLD)magnetic resonance imaging.Methods:Ten healthy childbearing women(age,22~28years.mean age,24.5years)underwent muscle BOLD MR imaging of the right calf in a cuff-compression model.The duration of the model was 160 s in resting phase,352 s in ischemic phase and 352 s in reactive hyperemia phase.The 3D-T1 WI images and the BOLD MR images of the upper calf muscle were performed by the 3.0 Tesla magnetic resonance scanner(Verio,Siemens,Erlangen,Germany).The turbo fast low angled shot squence was used to produce3D-T1 WI images.The single-shot gradient echo echo-planar sequence was used to produce the BOLD imaging.Preprocessing and analysis of BOLD MR data was carried out using DPARSFA v2.3,REST based on Matlab 2010 a and MRIcro N.Then the data is normalized by the following steps.At first,to calculate the average of the original signal intensity in the rest period160s(recorded as SImean),and then the original signal intensity of the whole time series(recorded as SItotal)devided by the average of the original signal intensity of the resting period,ie SItotal/SImean×100%.We measued the variables of soleus,tibialis anterior muscle,gastrocnemius muscle of the T2*normalized time signal curve in the second and fourteenth day of the menstrual cycle respectively.The variables were the signal intensity changes from cuff inflation to the end of the ischemic period(?SI1),the signal changes from the cuff deflation to T2* maximum(?SI2),and time to peak(TTP),which is the time interval between cuff deflation and T2* maximum.Paired-samples t test was used to analysis the above variables.Result:The result of the Paired-samples t test shows that the ?SI1,?SI2and TTP of the soleus muscle,tibialis anterior muscle and gastrocnemius muscle have no significant different between the second and fourteenth days of the menstrual cycle,and the p value was greater than 0.05.However,regardless of the menstrual cycle on the second day or the fourteenth day,seven volunteers of the soleus muscle,tibialis anterior muscle and gastrocnemius during the ischemic period showed a non-linear upward trend,the other three volunteers of the soleus muscle,tibialis anterior muscle and gastrocnemius muscle during the ischemic period showed a non-linear descending trend.Conclusion:Under the condition of this study,the skeletal muscle BOLD imaging of reproductive women in a cuff-compression model showed a trend of non-linear ascending or descending trend during the ischemia period.During the reaction hyperemia period,there was no significant difference in skeletal muscle BOLD signal between the second day and the fourteenth day of the menstrual cycle,that is,there is no significant difference in the vascularreactivity of the muscle tissue.