The Effects Of Hypoxia On The Mitochondrial Content And Functions Of Fetal Growth Restriction Placenta

Objective To investigate The effects of hypoxia on the mitochondrial content and functions of fetal growth restriction placenta.Methods FGR placentas(n = 14)and normal placentas(n = 16)were collected from singleton pregnancies.Real time quantitative PCR(q PCR)was used to detect mitochondrial DNA(mt DNA)content.Reverse transcription q PCR(RT-q PCR)was employed to detect the m RNA levels of mitochondrial encoding genes(DN6,COX I).Western blot analysis was performed to examine mitochondria-related protein levels.Hypoxia inducible factor-1α(HIF-1α)was also detected.In vitro,we established a model of trophoblast hypoxia using HTR-8/SVneo cells treated with 200 μM Co Cl2.Then,cell viability was evaluated by Cell Counting Kit-8.q PCR was used to detect mt DNA content.Reverse transcription q PCR(RT-q PCR)was employed to detect the m RNA levels of mitochondrial encoding genes(DN6,COX I).Western blot analysis was performed to examine mitochondria-related protein levels.The mitochondrial activities including intracellular ATP content and mitochondrial membrane potential were examined in model of trophoblast hypoxia.Moreover,the expression of LC3I/LC3 II,a marker for autophagy,was examined by Western blot.The co-location of GFP-LC3 puncta and mitochondria were detected to monitor the occurance of mitophagy in HTR-8/SVneo cells in the absence or presence of Co Cl2.Results In FGR placentas,the mt DNA,m RNA levels of mitochondrial coding genes(DN6,COX I),mitochondria-related protein(COX I,COX IV,VDAC)levels were all significantly lower than normal pregnancies.However,the expression of hypoxia indicated protein HIF-1αwas significantly increased.In the model of trophoblast hypoxia,the mt DNA and m RNA levels of mitochondrial coding genes were aslo significantly lower than control.Besides,mitochondrial function was impared,including decreased expression of mitochondria-related protei,decreased celluar ATP content and lower mitochondrial membrane potential.Moreover,occurance of mitophagy was detected by increased expression of LC3 II protein and the co-location of GFP-LC3 puncta and mitochondria in the model of trophoblast hypoxia.Conclusion The mitochondria in FGR placenta were impaired,showing the lowered mt DNA content and mitochondria dysfunction.Intrauterine hypoxia may contribute to the impaired mitohchondria,and hypoxia induced mitophagy may involve in this process.