Expression And Regulation Of LIF Gene In Rats During Peri-implantation And LIF Gene Knockout Rats

It is usually referred pregnancy as the process between successful implantation of the mammalian embryo and delivery.Successful implantation of the embryo,the establishment of pregnancy must have two conditions: the vitality and healthy embryos and receptive endometrium.Embryo implantation,including the localization,adhesion and invasion of the embryo in the uterine cavity,is a sign of successful pregnancy.The transition of the endometrium during the implantation window is due to the interaction of two kinds of ovarian hormones(estrogen and progesterone).Effect of two kinds of hormones on the endometrium was mediated by cytokine and growth factor produced by autocrine and paracrine.Leukemia inhibitory factor is essential for embryo implantation and decidualization.LIF combined with LIFR and gp130 to form a two mer complex,which activates MAP/JAK kinase,causing downstream STAT3 phosphorylation and working in the nucleus.This signal pathway is involved in the regulation of embryo implantation and decidualization.LIF protein expressing in rat early pregnancy days 1-5 in the glandular and luminal epithelium.The expression was increased gradually,and being the highest in the fifth day of pregnancy,indicating that LIF may be related to the establishment of rat uterine endometrium receptivity.LIF also play a role in rat embryo implantation.The expression of LIF protein was observed in the early stage of gestation on the day of 6-9,which indicated that LIF might play an important role in the process of decidua.gp130 mRNA has a weak expression in the early pregnancy fourth day of rat glandular epithelium,being located in the uterine glandular epithelium on the fifth day when it shows the strongest expression in the rat.And it is expressed in the embryo and uterus bed glandular epithelium on the early days 6-7 of pregnancy.These results suggest that gp130 is involved in the regulation of uterine gland secretion during implantation.The expression of gp130 m RNA at the uterus implantation site on day 8-9 indicating that gp130 may be involved in the process of endometrial decidua.In this study,the pattern of LIF and gp130 expression in rats early pregnancy was consistent with that of known STAT3 expression,proving that LIF and LIFR during implantation complexing with gp130,activating STAT3,regulating the embryo implantation and decidualization.In this study,7 different LIF knockout types were obtained by using TALEN technique.The sequencing results showed that the LIF gene was partially knocked out,and the heterozygous LIF knockout rats were obtained.The heterozygous LIF knockout rats were mated,LIF heterozygous knockout rat fertility,we counted 56 identification results of mating offspring,but not found LIF homozygous knockout rats.We found that wild type SD rat embryos and the number of heterozygous LIF knockout rats in selfed preimplantation embryos compared,significantly higher than the latter significantly(P < 0.01),the number of heterozygous LIF knockout rat inbred after preimplantation embryos with heterozygous LIF knockout inbred lines after birth except number offspring compared to significantly higher than the latter and the difference was significant(P < 0.05),and in the heterozygous LIF knockout inbred lines after preimplantation embryos to identify homozygous LIF knockout embryos,suggesting that the rats homozygous LIF knockout embryos may be developed in the process of embryo implantation after death or loss.LIF plays an important role in cell development and implantation.It was an important problem whether LIF had conservatism on functional and molecular mechanisms in different species.Currently,there is no report about the study of LIF knockout rat model.The rat was more close to the human in physiology,we used rat as the experimental animal,using the recently developed TALEN technology to obtain the LIF gene knockout rat heterozygote.In our previous experiments,we found that the results in rat was different in mice.Male and female LIF knockout rat heterozygous mating cannot obtain homozygous offspring,suggesting that LIF may play different roles in physiological,through different molecular mechanisms in different species(even in rats and mice).