| Goat placenta belongs to cotyledon type placenta,It has many important functions,such as hematopoiesis,transport,metabolism,endocrine,barrier and immunity,etc.After the placental circulation is established,the fetus through the placenta cotyledons to obtain nutrients.The mitochondria were oxidized to produce ATP in placental cotyledon cell,it can provide powerfor material exchange between mother and fetal.So placenta mitochondrial function normally is a key that to ensure the fetal growth anddevelopment,and maintaining a pregnancy.If the placental mitochondrial function is unnormal,it will lead toplacental material transport disorder,fetal weightreduce,even diseases such as intrauterine growth retardation.At present,there are few studies on the development of fetus and placenta during pregnancy,especially in the study of the mitochondrial structure and energy metabolism.Dazu Black goat is a genetic resource with high reproductive performance,mainly distributed in Dazu and surrounding areas.our previous results showed that Dazu black goat litter sizeandplacental efficiency was positively correlated,but the change of placental efficiency during pregnancy is not clear,while the lack of research on the relationship between placental mitochondrial energy metabolism and placental efficiency,these problems have limited our understanding of Dazu black goat placenta and pregnancy during the development of energy metabolic function.In this study,we observed the development of fetus and placenta in different stages of pregnancy,and compared the mitochondrial structure and energy metabolism,our aim was to investigate the placental efficiency and the structural and functional changes of placental mitochondria during pregnancy.In order to deeply analyze the effect of placenta on maintaining the normal pregnancy of Dazu black goat fetus.In this study,our experimental samples were Dazu black goat fetus and placenta 0n the 20,25,30,60,90 and 120 days of pregnancy,we were using HE staining,ultra microtransmission electron microscopy,enzyme catalysisto study on the changes of placental development and mitochondria in Dazu black goat.and using Real time quantitative PCR to study the expression of mitochondrial genes in placenta,The main results are as follows:1.In the early stage of pregnancy,the placenta was faster than the fetus.on the 30 day of pregnancy,the placenta was extended to the bilateral uterine horns.From 60 to 90 days of gestation,the fetus grew at a rate of 13.09 g/d,and the fetus grew at a rate of 34.911 g/d after a gestation of up to 120 days.Placental efficiency showed a trend of increasing gradually with the time of pregnancy,which increased from 0.194 to 2.692 on the 120 days of pregnancy,and the difference was very significant(P < 0.01).Placental structure changes by histological observation,the results showed that placental cells increased,the density increased,placenta formation chamber structure on the 20,25,30 days of pregnancy.After 60 days of pregnancy,the number of placental villi increased,length increased,and gradually into the myometrium.2.The ultrastructure of mitochondria was observed by electron microscope.The results showed that the morphology of placental mitochondria was complete,and a large number of mitochondria were gathered near the cotyledon.3.The activity of cytochrome C oxidase(CCO),succinate dehydrogenase(SDH),Ca++-Mg++-ATP and Na+-K+-ATP activities in placental cotyledon tissuewere measured.The results showed that in the course of pregnancy,the activity of mitochondria in placental cotyledon was significantly increased(P < 0.01).and 90 to 120 days of pregnancy showed a rising trend.The energy metabolism of mitochondria gradually increased.4.It is showed that the expression of COXIV、SDHA、TFAM、PGC-1ɑ、NRF-1 gene in placental cotyledon and uterine reached peak at 25 days of pregnancy,and then it was significantly reduced on the 30 days of pregnancy,such as the expression of mitochondrial COXIV gene decreased from 0.84 to 0.09 in cotyledons,significant difference(P < 0.01),the expression of nuclear gene PGC was reduced from 1.21 to 0.665 in cotyledons,the expression of nuclear gene NRF was reduced from 1.06 to 0.223 in cotyledons,the expression of nuclear gene TFAM decreased from 3.07 to 1.32 in the uterus.After 60 days of pregnancy,placental circulation has been established,the expression of mitochondrial genes in cotyledon tissue was increased,but the difference was not significant(P > 0.05).It showed that the placental efficiency was increased,the number of plancental mitochondria and energy metabolism were significantly enhanced with the rapid development of the fetus. |
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