RESUMEN
Objective To investigate the effect of pathologically elevated-cyclic stretch induced by hypertension on mitochondrial biogenesis of vascular smooth muscle cells (VSMCs), and the role of PGC1α in this process. Methods The Flexcell-5000T stretch loading system in vitro was applied to VSMCs with a frequency of 1. 25 Hz and an amplitude of 5% or 15% to simulate the mechanical environment under normal physiological or hypertensive pathological conditions respectively. Western blotting and qPCR were used to detect the expression of PGC1α, citrate synthase and mitochondrial DNA (mtDNA) copy number in VSMCs under normal physiological or hypertensive pathological conditions. VSMCs were treated with PGC1α specific activator ZLN005 to promote PGC1α expression or specific interfering fragment siRNA to inhibit PGC1α expression in order to detect the effect on citrate synthase and mtDNA copy number. Results Compared with 5% physiological cyclic stretch, 15% pathologically elevated-cyclic stretch significantly suppressed the expression of PGC1α, citrate synthase and mtDNA copy number in VSMCs. Compared with control group, the protein expression of PGC1α was significantly decreased and increased respectively. When VSMCs transfected with PGC1α siRNA or incubated PGC1α activator ZLN005, the expression of citrate synthase and mtDNA copy number were also significantly down regulated and up-regulated in VSMCs accordingly. Under physiological cyclic stretch conditions, the protein level of PGC1α was significantly down-regulated by PGC1α siRNA, which also significantly down-regulated citrate synthase expression and mtDNA copy number. The protein expression of PGC1α was significantly up-regulated by ZLN005, which also enhanced the expression of citrate synthase and mtDNA copy number. Conclusions The pathological cyclic stretch induced by hypertension significantly down-regulated the expression of citrate synthase and mtDNA copy number via suppressing the expression of PGC1α, resulting in mitochondrial dysfunction of VSMCs. PGC1α may be a potential therapeutic target molecule to alleviate the progression of hypertension.
RESUMEN
Objective@#To examine the correlation between exposure to polycyclic aromatic hydrocarbons ( PAHs ) and placental mitochondrial DNA ( mtDNA ) copy number among pregnant women, so as to provide the evidence for evaluation of potential effects of PAHs exposure during pregnancy on offspring health.@*Methods@#A total of 200 pregnant women delivered at a tertiary hospital in Urumqi City during the period from January to October 2019, and their newborns were recruited, and grouped according to the time of delivery, including the heating group [delivery during the heating period ( from January to April ) ] and the non-heating group [delivery during the non-heating period (from July to October) ]. Subjects'age, ethnicity, educational level and type of home heating were collected, and the total concentration of 16 PAHs was determined in the blood samples of pregnant women and their babies using gas chromatography-mass spectrometry. Placental DNA was extracted, and placental mtDNA copy number was measured using real-time fluorescence quantitative PCR assay. In addition, the correlation between PAHs concentration and placental mtDNA copy number was examined using the Spearman rank correlation analysis.@*Results@#There were 100 subjects in the heating group, which had a median age of 29 ( interquartile range, 3 ) years and had a mean gestational age of ( 275.06±0.72 ) days, and there were 100 subjects in the non-heating group, which had a median age of 29 ( interquartile range, 4 ) years and had a mean gestational age of ( 276.82±0.66 ) days. The total concentration of PAHs in the blood of pregnant women [15.71 (4.30) vs. 12.98 (5.49) μg/L; P<0.05 ], the total concentration of PAHs in neonatal blood [ 14.29 (4.25) vs. 11.24 (5.09) μg/L; P<0.05 ] and the placental mtDNA copy number [4.67 (1.18) vs. 4.51 (0.62); P<0.05] were all higher in the heating group than in the non-heating group. Spearman rank correlation analysis revealed that the total concentration of PAHs in the blood of pregnant women and neonates was positively correlated with placental mtDNA copy number ( rs=0.240, P=0.001; rs=0.273, P<0.001 ), and the total concentration of PAHs in the blood of pregnant women was positively correlated with the placental mtDNA copy number in the heating group ( rs=0.245, P=0.014 ), while the PAHs concentration in the neonatal blood was positively correlated with the placental mtDNA copy number in the non-heating group ( rs=0.292, P=0.003 ).@*Conclusions@#Exposure to PAHs positively correlates with placental mtDNA copy number among pregnant women, and there is a correlation between maternal exposure to PAHs and neonatal oxidative stress.
RESUMEN
Objective To explore the correlation between the changes of mitochondrial DNA (mtDNA) copy number of peripheral blood leukocytes and the degree of neurological impairment after traumatic brain injury (TBI).Methods A total of 40 Sprague Dawley rats were randomly divided into 4 groups:control group (n=10),mild TBI group (n=10),moderate TBI group (n=10) and severe TBI group (n=10).The cortical impact injury method to construct TBI rat model of different damage degree.The neurological score (mNSS,screen test,open field test) after TBI 24 h,48 h,72 h was performed and the orbital venous plexus blood genomic DNA was extracted.The real-time PCR method to measure the relative mitochondrial DNA copy number.After the experiment,the rats were euthanized,and the brain tissue was stained with hematoxylin-eosin staining(HE).Results There were significant differences in the HE staining findings of brain tissue pathology (P＜ 0.05).Each group of rats with brain injury after peripheral blood mtDNA copy number in 24 h (9.63±3.62,P＜0.05) and 48 h (9.80±3.58,P＜0.05) increased,began to decline at 72 h (4.97±2.68,P＜0.05).The rats mNSS scores were related with the mtDNA copy number after TBI 24 h (r=0.578,P＜0.05) and 48 h (r=0.559,P＜0.05),and not related to TBI 72 h (r=0.487,P＞0.05).The rats screen test scores were related with the mtDNA copy number after TBI 24 h (r=0.573,P＜0.05) and 48 h (r =0.501,P＜0.05),and not related to TBI 72 h (r=0.273,P＞0.05).The rats level scores of open field test were negatively correlated with the mtDNA copy number after TBI24 h (r=-0.662,P＜0.05) and 48 h (r=-0.507,P＜0.05),and not negatively correlated to TBI 72 h (r=-0.410,P＞0.05).The rats vertical scores of open field test were negatively correlated with the mtDNA copy number after TBI 24 h (r=-0.662,P＜0.05)and 48 h (r =-0.607,P＜ 0.05),and not negatively correlated to TBI 72 h (r =-0.141,P＞ 0.05).Conclusion TBI is related with the copy of early peripheral white blood cell number and mtDNA of rat nerve function damage,and mtDNA copy number of peripheral white blood cell may become a clinical evaluation of TBI neural function damage degree of a potential biomarker.