Live offspring produced by mouse oocytes derived from premeiotic fetal germ cells

Mature mouse oocytes currently can be generated in vitro from the primary oocytes of primordial follicles but not from premeiotic fetal germ cells. In this study we established a simple, efficient method that can be used to obtain mature oocytes from the premeiotic germ cells of a fetal mouse 12.5 days postcoitum (dpc). Mouse 12.5-dpc fetal ovaries were transplanted under the kidney capsule of recipient mice to initiate oocyte growth from the premeiotic germ cell stage, and they were recovered after 14 days. Subsequently, the primary and early secondary follicles generated in the ovarian grafts were isolated and cultured for 16 days in vitro. The mature oocytes ovulated from these follicles were able to fertilize in vitro to produce live offspring. We further show that the in vitro fertilization offspring were normal and able to successfully mate with both females and males, and the patterns of the methylated sites of the in vitro mature oocytes were similar to those of normal mice. This is the first report describing premeiotic fetal germ cells able to enter a second meiosis and support embryonic development to term by a combination of in vivo transplantation and in vitro culture. In addition, we have shown that the whole process of oogenesis, from premeiotic germ cells to germinal vesicle (GV)-stage oocytes, can be carried out under the kidney capsule.     

Growth of mouse oocytes to maturity from premeiotic germ cells in vitro

In the present study, we established an in vitro culture system suitable for generating fertilizable oocytes from premeiotic mouse female germ cells. These results were achieved after first establishing an in vitro culture system allowing immature oocytes from 12-14 day- old mice to reach meiotic maturation through culture onto preantral granulosa cell (PAGC) monolayers in the presence of Activin A (ActA). To generate mature oocytes from premeiotic germ cells, pieces of ovaries from 12.5 days post coitum (dpc) embryos were cultured in medium supplemented with ActA for 28 days and the oocytes formed within the explants were isolated and cocultured onto PAGC monolayers in the presence of ActA for 6-7 days. The oocytes were then subjected to a final meiotic maturation assay to evaluate their capability to undergo germinal vesicle break down (GVBD) and reach the metaphase II (MII) stage. We found that during the first 28 days of culture, a significant number of oocytes within the ovarian explants reached nearly full growth and formed preantral follicle-like structures with the surrounding somatic cells. GSH level and Cx37 expression in the oocytes within the explants were indicative of proper developmental conditions. Moreover, the imprinting of Igf2r and Peg3 genes in these oocytes was correctly established. Further culture onto PAGCs in the presence of ActA allowed about 16% of the oocytes to undergo GVBD, among which 17% reached the MII stage during the final 16-18 hr maturation culture. These MII oocytes showed normal spindle and chromosome assembly and a correct ERK1/2 activity. About 35% of the in vitro matured oocytes were fertilized and 53.44% of them were able to reach the 2-cell stage. Finally, around 7% of the 2-cell embryos developed to the morula/blastocyst stage.     

Maternal imprinting during mouse oocyte growth in vivo and in vitro

Epigenetic regulation of gene expression is critical for oogenesis in mammals. In this study, a simple and efficient method was used to obtain the oocytes from cultured fetal mouse ovaries of 12.5 dpc. The methylation pattern of these oocytes was examined. The results showed that the establishment of imprinting of Igf2r and Peg3 in oocytes derived from cultured fetal mouse germ cells in vitro follows a slower time course than that of oocytes in vivo. However, oocytes in vitro and in vivo share similar methylation patterns. Igf2r was gradually de novo methylated, and the methylation covers 80% CpG sites in oocytes cultured for 28 days. However, only 45% of the CpG sites is methylated in Peg3 at the same stage. Furthermore, it demonstrated that the degree of DNA methylation is positively correlated with the size of oocytes in vitro and in vivo, indicating a progressive methylation process during oocyte growth.     

Morphological characterization and meiotic competence of oocytes collected from filly ovaries

The effect of filly age on morphology of the ovaries, collected oocytes and their capacity for in vitro maturation (IVM) was examined. The ovaries of slaughtered fillies were classified into three groups, according to filly age: (I) <10 month old (<10MF); (II) approximately 1 year old (1YF); and (III) approximately 1.5 year old (1.5YF). The ovaries of mares were used as a control group. Ovarian morphology and collected oocytes were evaluated. Only oocytes with expanded (Ex) and compact (Cm) cumuli were used for IVM. In <10MF, 1YF, 1.5YF and mare groups, corpora lutea were found in the ovaries of 9.3%, 36.7%, 59.6% and 80.9% females, respectively (P < 0.001). Based on this observation, we found that about 37% of fillies reach puberty at approximately 12 months of age. No relationship was found between filly age and morphology of the oocytes obtained. In comparison to mares, fewer (P < 0.05) Cm oocytes were collected from filly ovaries. Among Cm groups, fewer filly (28.4-35.5%) than mare oocytes (50.0%) reached metaphase II stage, but the difference was only significant when compared to oocytes of the <10MF group (P < 0.05). In the Ex groups, a similar proportion of oocytes of fillies (40.8-51.1%) and mares (48.4%) attained the metaphase II stage. In conclusion, in the culture conditions applied, Cm oocytes of fillies younger than 10 months showed lower meiotic competence than mare oocytes. Oocytes of older fillies showed meiotic competence similar (P > 0.05) to mare oocytes. Both filly and mare oocytes with expanded cumuli displayed the same capacity for IVM.     

A study of meiosis in chimeric mouse fetal gonads

The influence of somatic environment on the onset and progression of meiosis in fetal germ cells was studied in chimeric gonads produced in vitro by dissociation-reaggregation experiments. Germ cells isolated from testes or ovaries of 11.5-13.5 days post coitum (dpc) CD-1 mouse embryos were loaded with the fluorescent supravital dye 5-6 carboxyfluorescein diacetate succinimyl ester (CFSE) and mixed with a cell suspension obtained by trypsin-EDTA treatment of gonads of various ages and of the same or opposite sex. Whereas 11.5 dpc donor germ cells appeared unable to survive in the chimeric gonads obtained, about 76% of the CFSE-labeled female germ cells obtained from 12.5 dpc donor embryos (premeiotic germ cells) found viable within host ovarian tissues showed a meiotic nucleus. In contrast, a smaller number (about 19%) were in meiosis in chimeric testes. None or very few of donor male germ cells entered meiosis in testes or ovarian host tissues. Aggregation of meiotic 13.5 dpc female germ cells with testis tissues from 13.5 to 14.5 dpc embryos resulted in inhibition of meiotic progression and pyknosis in most donor germ cells. These results support the existence of a meiosis-preventing substance or a factor causing oocyte degeneration in the fetal mouse testis, but not of a meiosis-inducing substance in the fetal ovary.     

Lyophilized somatic cells direct embryonic development after whole cell intracytoplasmic injection into pig oocytes

The study investigated the feasibility of lyophilization for long-term preservation of somatic cells and embryonic development after whole cell intracytoplasmic injection (WCICI) into enucleated pig oocyte. Confluent cultured porcine fetal fibroblast (pFF) cells were lyophilized and stored at 4 °C for at least 6 months. Results showed that compared to non-lyophilized control cells, lyophilized cells had drastically reduced cellular viability (P < 0.01). WCICI of reconstituted lyophilized cells could support complete embryonic development. However, the rates of cleavage (64.7 ± 2.7 vs. 43.5 ± 4.7%) and blastocyst formation (18.2 ± 0.6 vs. 10.2 ± 1.6%) were lower than that of control (P < 0.05). Total nuclei number per blastocyst (30.4 ± 4.5 vs. 25.2 ± 4.7) and intensity of acetylation at histone H3 (AcH3) protein (55.9 ± 3.5 vs. 53.3 ± 3.8) did not differ (P > 0.05). The development ability of embryos, produced from lyophilized somatic cells, was further increased (19.5 ± 2.4 vs. 10.2 ± 1.6%; P < 0.05) by treatment with trichostatin A (TSA) for 24 h post-activation. These TSA-treated embryos also had AcH3 level comparable with in vitro fertilized embryos (63.1 ± 3.2 vs. 69.9 ± 1.3). In conclusion, our results suggest that lyophilized somatic cells can direct embryonic development up to blastocyst stage after WCICI into pig oocytes. Treatment of embryos, produced from lyophilized somatic cells, with TSA can further increase their in vitro developmental potential.     

Developmental competence of frozen-thawed yak (Bos grunniens) oocytes followed by in vitro maturation and fertilization

In the present study, we examined the ability of immature germinal vesicle (GV) and subjected to in vitro matured (MII) yak oocytes to survive after cryopreservation as well as their subsequent development following in vitro maturation and fertilization. Both GV and MII oocytes were cryopreserved by using two different vitrification solutions (VS); VS-I contained 10% ethylene glycol (EG) and 10% dimethylsulfoxide (DMSO) in TCM-199 + 20% (v/v) fetal calf serum (FCS) whereas VS-II contained 40% EG + 18% Ficoll + 0.5 M sucrose in TCM-199 + 20% FCS. The percentage of oocytes found to be morphologically normal was greater (P < 0.01) in VS-I group than in VS-II group. Rates of cleavage (30.6–42.2%) and blastocyst formation (2.9–8.9%) did not differ among groups, but were lower than in unfrozen control (55.7% and 25.4%, P < 0.01). These results show that a combination of EG and DMSO or EG, Ficoll and sucrose can be used to cryopreserve yak oocytes in French straws.     

Epidermal growth factor can be used in lieu of follicle-stimulating hormone for nuclear maturation of porcine oocytes in vitro

Epidermal growth factor (EGF) has been considered a potential regulator of meiotic and cytoplasmic maturation in mammalian oocytes, but inconsistencies exist between earlier studies, probably due to differences in the culture conditions used. Using a serum- and hormone-free in vitro maturation (IVM) medium, this study investigated the specific contribution of EGF on IVM of porcine (Sus scrofa) oocytes and its interactive effects with follicle-stimulating hormone (FSH), porcine follicular fluid (pFF), cumulus cells, and serum. It was noteworthy that EGF functionally mimicked the action of FSH and could completely replace FSH for nuclear maturation (83.2 ± 4.4% vs. 55.9 ± 5.2%; mean ± SEM), whereas EGF had a synergistic effect with FSH on cytoplasmic maturation of porcine oocytes (P < 0.05). Specific inhibition of EGF receptor (EGFR) by tyrphostin AG 1478 inhibited both EGF- and FSH-induced meiotic resumption (17.9 ± 5.2% and 18.2 ± 4.4%, respectively), thereby suggesting that EGFR signaling pathway was essential for oocyte reentry into the meiotic cell cycle. Furthermore, it is possible that FSH action occurs via the EGFR signaling pathway to induce meiotic maturation, although alternate pathways could not be excluded. There were also individual or combined effects of cumulus cells, FSH, serum, and pFF with EGF on IVM of porcine oocytes (P < 0.05). Although FSH had a synergistic effect with EGF on cytoplasmic maturation, pFF masked the effects of EGF on both nuclear and cytoplasmic maturation of porcine oocytes (P < 0.05). Moreover, the presence of cumulus cells was essential for EGF action. In conclusion, a defined system was used to better examine the effects of EGF. We inferred that EGF functionally mimics FSH for nuclear maturation of porcine oocytes, and its exogenous supplementation into IVM medium can optimize the beneficial effects of FSH on cytoplasmic maturation of oocytes to obtain enhanced embryo development in vitro.     

Characterization,expression and localization of valosin-containing protein in ovaries of the giant tiger shrimp Penaeus monodon

Valosin-containing protein (VCP), a member of the ATPase-associated with diverse cellular activity (AAA) family, was identified from the giant tiger shrimp (Penaeus monodon). The full-length cDNA of the PmVCP mRNA consisted of 2724 bp containing an ORF of 2367 bp corresponding to a deduced polypeptide of 788 amino acids. The deduced PmVCP protein contained two putative Cdc48 domains (positions 17–103, E-value = 2.00e− 36 and 120–186, E-value = 3.60e− 11) and two putative AAA domains (positions 232–368, E-value = 3.67e− 24 and 505–644, E-value = 3.73e− 25). PmVCP mRNA expression in ovaries was greater than that in testes in both juveniles and broodstock. PmVCP was significantly up-regulated in stages II and IV ovaries in intact wild broodstock (P < 0.05) but it was not differentially expressed during ovarian development in eyestalk-ablated broodstock (P > 0.05). The expression level of PmVCP mRNA in ovaries of 14-month-old shrimp was not affected by progesterone injection (0.1 μg/g body weight, P > 0.05). In contrast, exogenous 5-HT administration (50 μg/g body weight) resulted in an increase of PmVCP mRNA in ovaries of 18-month-old shrimp at 6 and 24 h post-injection (hpi) (P < 0.05). The rPmCdc48-VCP protein and its polyclonal antibody were successfully produced. Cellular localization revealed that PmVCP was localized in the ooplasm of previtellogenic oocytes. Subsequently, it was translocated into the germinal vesicle of vitellogenic oocytes. Interestingly, PmVCP was found in nucleo-cytoplasmic compartments, in the cytoskeletal architecture and in the plasma membrane of mature oocytes in both intact and eyestalk-ablated broodstock.     

Primordial follicle assembly was regulated by notch signaling pathway in the mice

Notch signaling pathway, a highly conserved cell signaling system, exists in most multicellular organisms. The objective of this study was to examine Notch signaling pathway in germ cell cyst breakdown and primordial follicle formation. The receptor and ligand genes of Notch pathway (Notch1, Notch2, Jagged1, Jagged2 and Hes1) were extremely down-regulated after newborn mouse ovaries were cultured then exposed to DAPT or L-685,458 in vitro (P < 0.01). Since DAPT or L-685,548 inhibits Notch signaling pathway, the expression of protein LHX8 and NOBOX was significantly reduced during the formation of the primordial follicles. Down-regulated mRNA expression of specific genes including Lhx8, Figla, Sohlh2 and Nobox, were also observed. The percentages of female germ cells in germ cell cysts and primordial follicles were counted after culture of newborn ovaries for 3 days in vitro. The result showed female germ cells in cysts was remarkably up-regulated while as the oocytes in primordial follicles was significantly down-regulated (P < 0.05). In conclusion, Notch signaling pathway may regulate the formation of primordial follicle in mice.     

Retinoic acid derived from the fetal ovary initiates meiosis in mouse germ cells

Meiotic initiation of germ cells at 13.5 dpc (days post‐coitus) indicates female sex determination in mice. Recent studies reveal that mesonephroi‐derived retinoic acid (RA) is the key signal for induction of meiosis. However, whether the mesonephroi is dispensable for meiosis is unclear and the role of the ovary in this meiotic process remains to be clarified. This study provides data that RA derived from fetal ovaries is sufficient to induce germ cell meiosis in a fetal ovary culture system. When fetal ovaries were collected from 11.5 to 13.5 dpc fetuses, isolated and cultured in vitro, germ cells enter meiosis in the absence of mesonephroi. To exclude RA sourcing from mesonephroi, 11.5 dpc urogenital ridges (UGRs; mesonephroi and ovary complexes) were treated with diethylaminobenzaldehyde (DEAB) to block retinaldehyde dehydrogenase (RALDH) activity in the mesonephros and the ovary. Meiosis occurred when DEAB was withdrawn and the mesonephros was removed 2 days later. Furthermore, RALDH1, rather than RALDH2, serves as the major RA synthetase in UGRs from 12.5 to 15.5 dpc. DEAB treatment to the ovary alone was able to block germ cell meiotic entry. We also found that exogenously supplied RA dose‐dependently reduced germ cell numbers in ovaries by accelerating the entry into meiosis. These results suggest that ovary‐derived RA is responsible for meiosis initiation. J. Cell. Physiol. 228: 627–639, 2013. © 2012 Wiley Periodicals, Inc.     

Mouse oocytes derived from fetal germ cells are competent to support the development of embryos by in vitro fertilization

Mouse oocyte development in vitro has been studied in the past several years, but no evidence showed that the fertilizable oocytes could be obtained from the fetal mouse germ cells before the formation of the primordial follicles. In this study, an efficient and simple method has been established to obtain the mature oocytes from the fetal mouse germ cells at 16.5 days post-coitum (dpc). For the initial of follicular formation, fetal mouse 16.5 dpc ovaries were transplanted to the recipient under the kidney capsule, and the ovaries were recovered after 14 days. Subsequently, the growing preantral follicles in the ovarian grafts were isolated and cultured in vitro for 12 days. Practically, the mature oocytes ovulated from the antral follicles were able to be fertilized in vitro and support the embryonic development. The results demonstrate that the fetal mouse 16.5 dpc germ cells are able to form primordial follicles with the ovarian pregranulosa cells during the period of transplantation in the ectopic site, and the oocytes within the growing follicles are able to mature in vitro, then are able to support the embryonic development.     

Nuclear maturation and embryo development of porcine oocytes vitrified by cryotop: Effect of different stages of in vitro maturation

The present study was designed to evaluate the viability, meiotic competence and subsequent development of porcine oocytes vitrified using the cryotop method at different stages of in vitro maturation (IVM). Cumulus–oocyte complexes (COCs) were cultured in IVM medium supplemented with 1 mM dibutyryl cAMP (dbcAMP) for 22 h and then for an additional 22 h without dbcAMP in the medium. Germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I (MI), anaphase I/telophase I (AI/TI) and metaphase II (MII) were found to occur predominantly at 0–22, 26, 32, 38 and 44 h of IVM, respectively. Oocytes were exposed to cryoprotectant (CPA) or vitrified after different durations of IVM (0, 22, 26, 32, 38 and 44 h). After CPA exposure and vitrification, surviving oocytes that were treated before completion of the 44 h maturation period were placed back into IVM medium for the remaining maturation period, and matured oocytes were incubated for 2 h. CPA treatment did not affect the viability of oocytes matured for 26, 32, 38 or 44 h, but significantly decreased survival rate of oocytes matured for 0 or 22 h. CPA treatment had no effect on the ability of surviving oocytes to develop to the MII stage regardless of the stage during IVM; however, blastocyst formation following PA was severely lower (P < 0.05) than that in the control. At 2 h post-warming, the survival rates of oocytes vitrified at 26, 32, 38 and 44 h of IVM were similar but were higher (P < 0.05) than those of oocytes vitrified at 0 or 22 h of IVM. The MII rates of surviving oocytes vitrified at 0 and 38 h of IVM did not differ from the control and were higher (P < 0.05) than those of oocytes vitrified at 22, 26 or 32 h of IVM. After parthenogenetic activation (PA), both cleavage and blastocyst rates of vitrified oocytes matured for 22, 26, 32, 38 and 44 h did not differ, but all were lower (P < 0.05) than those matured 0 h. In conclusion, our data indicate that survival, nuclear maturation and subsequent development of porcine oocytes may be affected by their stage of maturation at the time of vitrification; a higher percentage of blastocyst formation can be obtained from GV oocytes vitrified before the onset of maturation.     

Celastrol protects human neuroblastoma SH-SY5Y cells from rotenone-induced injury through induction of autophagy

Celastrol, an active component found in the Chinese herb tripterygium wilfordii has been identified as a neuroprotective agent for neurodegenerative diseases including Parkinson’s disease (PD) through unknown mechanism. Celastrol can induce autophagy, which plays a neuroprotective role in PD. We tested the protective effect of celastrol on rotenone-induced injury and investigated the underlying mechanism using human neuroblastoma SH-SY5Y cells. The SH-SY5Y cells were treated with celastrol before rotenone exposure. The cells survival, apoptosis, accumulation of α-synuclein, oxidative stress and mitochondrial function, and autophagy production were analyzed. We found celastrol (500 nM) pre-treatment enhanced cell viability (by 28.99%, P < 0.001), decreased cell apoptosis (by 54.38%, P < 0.001), increased SOD and GSH (by 120.53% and 90.46%, P < 0.01), reduced accumulation of α-synuclein (by 35.93%, P < 0.001) and ROS generation (by 33.99%, P < 0.001), preserved MMP (33.93 ± 3.62%, vs. 15.10 ± 0.71% of JC-1 monomer, P < 0.001) and reduced the level of cytochrome C in cytosol (by 45.57%, P < 0.001) in rotenone treated SH-SY5Y cells. Moreover, celastrol increased LC3-II/LC3 I ratio by 60.92% (P < 0.001), indicating that celastrol activated autophagic pathways. Inhibiting autophagy by 3-methyladenine (3-MA) abolished the protective effects of celastrol. Our results suggested that celastrol protects SH-SY5Y cells from rotenone induced injuries and autophagic pathway is involved in celastrol neuroprotective effects.     

CHFR is important for the survival of male premeiotic germ cells

DNA damage response is required for male fertility. DNA damage repair mediates recombination between homologous chromosomes in meiotic prophase, which is essential for proper chromosome segregation during meiotic division. Interestingly, some DNA damage response proteins are also required for the survival of premeiotic germ cells, but their roles in these cells are still unclear. CHFR was recently shown to participate in DNA damage response, but it remains to be established if CHFR is required for male fertility. In this study, we characterized Chfr knockout male mice and found that around 30% of them were infertile. The onset of spermatogenesis was delayed and there was significant increase in apoptosis in premeiotic germ cells. This resulted in complete loss of germ cells in testes in 3 months and azoospermia in these mice. We further demonstrated that ATM activation was compromised in the testes of these mice. Therefore, CHFR is important for the survival of male premeiotic germ cells, which is likely through maintaining genomic stability in spermatogonial stem cells.     

Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes

Bisphenol A (BPA) is an estrogenic environmental toxin widely used for the production of plastics. Frequent human exposure to this chemical has been proposed to be a potential public health risk. The objective of this study was to assess the effects of BPA on germ cell cyst breakdown and primordial follicle formation. Pregnant mice were treated with BPA at doses of 0, 0.02, 0.04, 0.08 mg/kg body weight/day from 12.5 day postcoitum. BPA was delivered orally to pregnant female mice. A dose–response relationship was observed with increased BPA exposure level associated with more oocytes in germ cell cyst and less primordial follicle at postnatal day 3 (P < 0.01). Progression to meiosis prophase I of oocytes was delayed in the 0.08 mg/kg bw/day treated group (P < 0.01). Decreased mRNA expression of specific meiotic genes including Stra8, Dmc1, Rec8 and Scp3 were observed. In conclusion, BPA exposure can affect the formation of primordial follicle by inhibiting meiotic progression of oocytes.     

Expression and proliferation profiles of PKC,JNK and p38MAPK in physiologically stretched human bladder smooth muscle cells

Objective

To determine protein kinase C (PKC), c-Jun NH2-Terminal Kinase (JNK) and P38 mitogen-activated protein kinases (p38MAPK) expression levels and effects of their respective inhibitors on proliferation of human bladder smooth muscle cells (HBSMCs) when physiologically stretched in vitro.

Materials and methods

HBSMCs were grown on silicone membrane and stretch was applied under varying conditions; (equibiaxial elongation: 2.5%, 5%, 10%, 15%, 20%, 25%), (frequency: 0.05, 0.1, 0.2, 0.5, 1 Hz). Optimal physiological stretch was established by assessing proliferation with 5-Bromo-2-deoxyuridine (BrdU) assay and flow cytometry. PKC, JNK and p38 expression levels were analyzed by Western blot. Specificity was maintained by employing specific inhibitors; (GF109203X for PKC, SP600125 for JNK and SB203580 for p38MAPK), in some experiments.

Results

Optimum proliferation was observed at 5% equibiaxial stretch (BrdU: 0.837 ± 0.026 (control) to 1.462 ± 0.023)%, (P < 0.05) and apoptotic cell death rate decreased from 16.4 ± 0.21% (control) to 4.5 ± 0.13% (P < 0.05) applied at 0.1 Hz. Expression of PKC was upregulated with slight increase in JNK and no change in p38MAPK after application of stretch. Inhibition had effects on proliferation (1.075 ± 0.024, P < 0.05 GF109203X); (1.418 ± 0.021, P > 0.05 SP600125) and (1.461 ± 0.01, P > 0.05 SB203580). These findings show that mechanical stretch can promote magnitude-dependent proliferative modulation through PKC and possibly JNK but not via p38MAPK in hBSMCs.     

Circulating obestatin is increased in patients with cardiorenal syndrome and positively correlated with vasopressin

Obestatin regulates fluid and electrolyte homeostasis mainly by opposing the action of vasopressin (AVP). We measured plasma concentration of obestatin and AVP in patients with cardiorenal syndrome (CRS). Plasma AVP and obestatin concentration were measured in 34 patients with type II CRS. The data were compared to that in 31 patients with chronic kidney disease (CKD), 41 patients with chronic heart failure (CHF) and 30 healthy subjects. Obestatin was significantly higher in the patients with CRS (355.8 ± 85.1 pg/ml) than that in the healthy controls (212.3 ± 37.9 pg/ml, P < 0.01), the patients with CKD (246.7 ± 34.3 pg/ml, P < 0.01) and the patients with CHF (258.4 ± 112.1 pg/ml, P < 0.01). AVP was also significantly higher in the patients with CRS (65.1 ± 36.0 pg/ml) than that in the healthy controls (38.5 ± 20.1 pg/ml, P < 0.01), the patients with CKD (50.4 ± 24.8 pg/ml, P < 0.01) and the patients with CHF (54.6 ± 16.3 pg/ml, P < 0.01). Plasma concentration of obestatin was positively correlated with AVP plasma concentration in the overall analysis that included subjects from all disease categories (r = 0.219, P < 0.05), but not within the CRS group. Plasma obestatin and vasopressin were elevated in patients with CRS. Plasma obestatin concentration seemed to be positively correlated with plasma AVP.     

小鼠生殖细胞的胚胎发育

本文综述了近年来小鼠胚胎发育过程中生殖细胞的起源、迁移与增殖、性别分化及其基因组修饰等方面的研究进展。小鼠生殖细胞在7~7.5dpc时由原始生殖细胞（PGC）演变而来,至12.5dpc时PGC全部迁移进入生殖嵴,到13.5dpc时停止分裂。Steel/c-kit信号途径在PGC迁移过程中起重要作用。生殖细胞的性别主要是由生殖腺中体细胞的微环境决定的。Y染色体上存在精子形成所必需的基因。生殖细胞的全基因组范围的重新甲基化晚于胚胎体细胞的重新甲基化,到18.5dpc时才完成。雌性生殖细胞的X染色体重新活化在14.5~15.5dpc时完成,并且与生殖嵴的性别分化无关。 Abstract:This paper reviewed the recent progress of the origin,migration and proliferation,sex determination,and genomic modification of murine germ cells during its embryonic development. Murine germ cells originate from primordial germ cells at about 7~7.5dpc. Then PGCs migrated into germinal ridge at about 12.5dpc during which Steel/c-kit signal pathway plays important roles and stopped division at 13.5dpc. The sex of germ cells was mainly determined by the soma microenvironment in the gonad. And there are essential genes for sperm formation on the Y chromosome. The de novo methylation of murine germ cells was much later than soma cells and was completed at about 18.5dpc. The X chromosome reactivation of female germ cells was finished at about 14.5~15.5dpc which was independent of sexual differentiation of germinal ridge.