Anti-apoptotic activity of porcine cFLIP in ovarian granulosa cell lines

In mammalian ovaries, more than 99% of follicles undergo atresia during growth and development. Recently, we found that the expression of cellular FLICE-like inhibitory protein long form (cFLIP(L)) decreased during follicular atresia in granulosa cells of porcine ovaries. In humans and other species, both the short (cFLIP(S)) and long (cFLIP(L)) forms of cFLIP are considered to function as cell survival factors that inhibit death ligand receptor-mediated apoptosis. Since the anti-apoptotic activity of porcine cFLIP (pcFLIP) in granulosa cells had not been determined, we examined the effect of pcFLIP on survival using granulosa-derived cell lines. A human cervix adenocarcinoma cell line, HeLa, human ovarian granulosa tumor cell line, KGN, and porcine granulosa-derived cell line, JC-410, were used. By Western blotting, internal cFLIP(L) was detected in all cell lines, but only trace levels of cFLIP(S) were found in HeLa and KGN cells. To examine the anti-apoptotic activity, pcFLIP(S) or pcFLIP(L) was overexpressed in HeLa and KGN cells. Transfected cells in which pcFLIP(S) or pcFLIP(L) was overexpressed, survived the induction of Fas-mediated apoptosis, while almost all of the cells transfected with empty vector died. Then, we suppressed the expression of porcine cFLIP(S) and/or cFLIP(L) in JC-410 cells using small interfering RNA (siRNA). When both cFLIP(S) and cFLIP(L), or only cFLIP(L) was suppressed, cell viability declined significantly. From the results, we conclude that porcine cFLIP(S) and cFLIP(L) exhibit anti-apoptotic activity in granulosa-derived cells. It was strongly suggested that pcFLIP acts as a survival-promoting factor in granulosa cells and determines whether porcine ovarian follicles survive or undergo atresia.

A novel strategy for preventing human CD8+ cytotoxic T lymphocyte-mediated cytotoxicity against pig endothelial cells by overexpression of pig cellular FLICE-like inhibitory protein (c-FLIP) gene

Human CD8+ cytotoxic T lymphocyte (CTL)-mediated cytotoxicity in xenograft recipients is an important obstacle for successful xenotransplantation of pig organs into humans. In our previous study, we demonstrated that xenocytotoxicity of human CD8+ CTL detrimental to pig endothelial cells (PEC) is mediated mainly by the Fas/FasL apoptotic pathway. Furthermore, we developed new methods to prevent this CTL killing by extracellular remodeling using overexpression of human decoy Fas antigen and membrane-bound human FasL on pig xenograft cells. The cellular FLICE-inhibitory protein (c-FLIP), a caspase-8 inhibitor that lacks the cysteine domain, is a negative regulator of death receptor-mediated apoptosis. c-FLIP proteins exist as long (c-FLIP(L)) and short (c-FLIPs) splice variants, both capable of protecting cells from death receptor-mediated apoptosis. In this report, we have demonstrated that both pig c-FLIPs and pig c-FLIP(L) significantly inhibit human CD8+ CTL-mediated xenocytotoxicity toward stably transfected PEC, although the expression level of pig Fas antigen on cell surface was not changed. These data suggested that intracellular remodeling with overexpression of pig c-FLIP in xenograft cells may decrease the innate cellular responses against xenografts, facilitating long-term xenograft survival.

The effect of feeding piglets with the diet containing green tea extracts or coumarin on in vitro metabolism of aflatoxin B1 by their tissues

To clarify whether enzymes involved in aflatoxin B1 (AFB1) metabolism in pigs respond to antioxidant agents, the effect of feeding piglets with diets containing green tea extracts (Sunphenon) and coumarin on in vitro AFB1 metabolism by their liver and intestinal tissues was studied. The results showed that coumarin reduced AFB1-DNA adduct formation by both liver and intestinal microsomes, while Sunphenon did not have any effects. Both coumarin and Sunphenon enhanced the glutathione S-transferase (GST) activity to conjugate AFB1 to glutathione GSH in the intestine, although no effects were noted in the liver. Changes of the expression of mRNA of GSTA2 and GSTO1 were not in parallel with the observed changes of GST activity, suggesting that other GST subtypes are involved in the GST activity toward AFB1. As for lipophilic-free AFB1 metabolites, coumarin reduced the liver microsomal conversion of AFB1 to aflatoxin M1 (AFM1) and aflatoxin Q1 (AFQ1), but Sunphenon exerted no effects. Both coumarin and Sunphenon enhanced the conversion of AFB1 to aflatoxicol in the liver. All the results suggest that feeding with a diet containing coumarin affects AFB1 metabolism to enhance AFB1 detoxification through the suppression of P450 enzyme activity in the liver and the enhancement of GST activity in the intestine. Feeding with a diet containing Sunphenon enhances AFB1 detoxification, but the effects are noted mainly in the intestine.

Cooperative interaction between ETS1 and GFI1 transcription factors in the repression of Bax gene expression

The proto-oncoproteins ETS1 and growth factor independent-1 (GFI1) are implicated in cell growth and differentiation in various types of cells, and their deregulated expression is involved in malignant transformation. Here, we report that ETS1 and GFI1 interact and affect gene expression through their cross-talk. Co-immunoprecipitation analyses and glutathione-S-transferase pull-down assays revealed that ETS1 bound directly to GFI1 via its Ets domain, and GFI1 bound to ETS1 via its zinc-finger domain. Luciferase (Luc) assays using artificial reporters showed that GFI1 repressed ETS1-mediated transcriptional activation and ETS1 repressed GFI1-mediated transcriptional activation, in a dose-dependent manner. However, in the Bax promoter where the Ets- and Gfi-binding sites (EBS and GBS) are adjacent, ETS1 and GFI1 cooperatively reduced activation. Site-directed mutagenesis on the EBS and GBS of the Bax promoter showed that both binding sites were necessary for full repression. Chromatin immunoprecipitation analyses confirmed that an ETS1-GFI1 complex formed on the Bax promoter even when either EBS or GBS was mutated. Introduction of small interfering RNA against ETS1 and/or GFI1 enhanced endogenous Bax gene expression. Our results suggest that the interaction between ETS1 and GFI1 facilitates their binding to specific sites on the Bax promoter and represses Bax expression in vivo.

Changes in Expression and Localization of GPRC5B and RAR.ALPHA. in the Placenta and Yolk Sac During Middle to Late Gestation in Mice

The mRNA expression of GPRC5B, an orphan G protein-coupled receptor, is induced by retinoic acid (RA). Because RA plays critical roles in embryonic development, reproductive functions, metabolism and homeostasis, GPRC5B is also considered crucial in these physiological events. We investigated the changes in expression of GPRC5B and RA receptor (RAR) alpha mRNAs and immunohistochemical localization of their proteins in the murine placenta and yolk sac at 13.5, 15.5 and 17.5 days post coitus. Stable levels of GPRC5B and RARalpha mRNAs were detected in the placenta and yolk sac. In the placenta, GPRC5B was present in maternal and fetal vascular endothelial cells, stromal cells, fibroblast-like cells and glycogen cells. A strong reaction to RARalpha was detected in maternal and fetal vascular endothelial cells and stromal cells. The levels of GPRC5B and RARalpha proteins in maternal and fetal vascular endothelial cells decreased with gestation. In the yolk sac, GPRC5B and RARalpha proteins were detected in vascular endothelial cells, but their levels did not change during the gestation period. These findings indicate that GPRC5B is involved in RA-dependent morphogenesis/angiogenesis and regulation of extracellular matrix synthesis in the murine placenta and yolk sac.

Production of the first offspring from oocytes derived from fresh and cryopreserved pre-antral follicles of adult mice

Although mammalian ovaries contain hundreds of thousands of pre-antral follicles, fewer than 1% of these reach maturity and ovulation. Obtaining immature eggs from the pre-antral follicles of ovarian tissue could increase the possibility of preserving fertility in women undergoing anti-cancer treatment, and in women who wish to delay pregnancy and child raising until they are older. This study reports the birth of 10 healthy mouse pups derived from oocytes obtained from pre-antral follicles after adult ovary tissue cryopreservation and allotransplantation. High in-vitro maturation (55.1%), fertilization (76.3%) and cleavage (98.3%) rates were achieved using these oocytes, and there was no significant difference between the vitrified and control samples except in maturation rate (55.1 versus 72.8%, P < 0.05). After an ultra-rapid vitrification procedure, the warmed tissue fragments were transplanted beneath the kidney capsule of severe combined immunodeficient mice for onward in-vivo culture. Within 10 days of culture, 138 full size oocytes developed from the 456 transplanted pre-antral follicles. In-vivo growth of follicles was followed by in-vitro oocyte maturation, in-vitro fertilization and subsequent embryo transfer, leading to the birth of 10 healthy pups. These results may lead to increasing the possibility of preserving fertility by cryopreservation of ovarian tissue.

Molecular Cloning of Porcine (Sus scrofa) Tumor Necrosis Factor Receptor 2

Tumor necrosis factor (TNF) alpha can induce both cell death and proliferation by binding to either TNF receptor (TNFR) 1 or 2. In the granulosa cells of porcine ovaries, TNFalpha is considered to act as an anti-apoptotic/survival factor during follicular atresia. As a first step toward elucidating the function of TNFR2 in regulating follicular development/growth and atresia in porcine ovaries, we isolated the porcine (Sus scrofa) cDNA encoding TNFR2, which was identified from a cDNA library prepared from the follicular granulosa cells of pig ovaries. Porcine TNFR2 (1,125 bp, 375 amino acid residues), which contains specific amino acid region of transmembrane, indicated high identities with human and murine TNFR2 (78 and 69% at mRNA level, respectively; 73 and 61% at protein level, respectively), suggesting that the function of porcine TNFR2 is similar to that of human and murine homologues. Understanding the expression patterns of porcine TNFR2 mRNA in various organs, which we confirmed by reverse transcription polymerase chain reaction analysis, would help to elucidate the physiological role of TNFR2 in the regulation of apoptosis in porcine organs.

Molecular Characteristics of Porcine Fas-associated Death Domain (FADD) and Procaspase-8

To reveal the intracellular signal transduction molecules involved in granulosa cell apoptosis in porcine ovarian follicles, we cloned the porcine Fas-associated death domain (FADD), an adaptor protein for the cell death receptor, and procaspase-8, an initiator caspase. Porcine FADD (pFADD) was 636 bp (211 amino acids: aa) long and showed 74.0 and 65.4% homology with human and murine FADD, respectively. Porcine procaspase-8 (pprocaspase-8) was 1,431 bp (476 aa) long and 70.6 and 63.4% homologous with human and murine procaspase-8, respectively. To confirm the apoptosis-inducing abilities, we constructed pFADD and pprocaspase-8 cDNA expression vectors with enhanced green fluorescence protein (EGFP) and then transfected them into human uterine cervix tumor (HeLa-K), human granulosa cell-derived (KGN), murine granulosa-derived tumor (KK1), and porcine granulosa cell-derived (JC410) cells. When pFADD and pprocaspase-8 were overexpressed, cell death was induced in these transfected cells. However when caspase-inhibitor p35 was cotransfected, cell death was inhibited. The pFADD and pprocaspase-8 genes are well conserved, as are the physiological functions of their products.

The Role of Interleukin-6 in the Regulation of Granulosa Cell Apoptosis During Follicular Atresia in Pig Ovaries

More than 99% of follicles in mammalian ovaries undergo a degenerative process known as atresia, and only a few follicles actually ovulate during follicular growth and development. Follicular selection mostly depends on granulosa cell apoptosis, but the molecular mechanism behind the regulation of this selective atresia is still largely unknown. In the present study, to examine whether or not interleukin-6 (IL-6), a multifunctional cytokine, is involved in apoptosis during atresia in pig ovaries, the expression of IL-6 mRNA in granulosa cells was quantified by real-time reverse transcription-polymerase chain reaction (RT-PCR). The level of mRNA decreased during atresia. Enzyme-linked immunosorbent assay (ELISA) showed that the level of IL-6 protein in follicular fluid also decreased during atresia. Moreover, recombinant human IL-6 upregulated the expression of an intracellular apoptosis inhibitor, cellular FLICE-like inhibitory protein long form (cFLIP(L)), in cultured cells derived from human granulosa cells. It is possible that IL-6 is produced in the granulosa cells of healthy follicles, that it increases the cFLIP(L) level, and cFLIP(L) then prevents apoptotic cell death.

Changes in Expression of Interleukin-6 Receptors in Granulosa Cells During Follicular Atresia in Pig Ovaries

More than 99% of follicles undergo a degenerative process known as "atresia" in mammalian ovaries, and only a few follicles ovulate during follicular growth and development. Follicular selection predominantly depends on granulosa cell apoptosis. To reveal the molecular mechanisms of selective follicular atresia, we examined the changes in the levels of interleukin-6 (IL-6) receptors expressed in the granulosa cells of pig ovaries. The levels of IL-6 receptor (IL-6R)-alpha mRNA and protein in granulosa cells were quantified by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. IL-6R alpha mRNA and protein were highly expressed in the granulosa cells of progressed atretic follicles. Enzyme-linked immunosorbent assay showed that the expression of IL-6 soluble receptor (IL-6sR) protein in follicular fluid decreased during atresia. Moreover, we isolated porcine cDNA encoding an IL-6 signal transducer, gp130. Porcine gp130 (2,754 bp and 917 amino acids) was identified from a cDNA library prepared using follicular granulosa cells of pig ovaries. Porcine gp130 was highly homologous with human and murine gp130. RT-PCR analysis revealed that the level of gp130 mRNA also decreased during atresia. We presume that IL-6sR and gp130, but not IL-6R alpha, play important roles in regulation of granulosa cell survival.

Oocyte growth and acquisition of meiotic competence

Ovaries contain a huge number of non-growing and growing oocytes. Once non-growing oocytes (pig and cow: 30 microm in diameter) in primordial follicles enter the growth phase, they grow toward their final size (120-125 microm) taking a long period of time. The small oocytes have no ability to mature because of the inability to activate Cdc2 kinase and MAP kinase that are required for maturation. During the final growth phase, oocytes acquire the ability to activate these kinases. The population of the oocytes that grow to the final size is quite small in the ovary. Artificially growing-up of small oocytes could provide a new source of mature eggs for livestock production and assisted reproduction in humans. Baby mice have been produced by in vitro grown oocytes from primordial follicles. In large domestic species, only two baby calves have been produced from cultured oocytes that were at the mid-growth phase (90-99 microm) from early antral follicles. A culture system for the oocytes in secondary or smaller follicles has not been established. Xenotransplantation of oocytes to immunodeficient mice is a substitute for the culture. Bovine secondary follicles (oocyte: 55 microm) developed to the antral stage with oocytes reaching their final size in xenografts after 2 months. The grown oocytes matured and were penetrated by spermatozoa. Bovine and porcine primordial follicles (oocyte: 30 microm) developed to the antral stage after 6 months. In vitro growth and xenotransplantation systems will provide a new understanding of the mechanisms regulating oogenesis and folliculogenesis in the ovary.

Temporal and topographic profiles of tissue hypoxia following transient focal cerebral ischemia in rats

Intravascular accumulation of blood cells after brain ischemia-reperfusion can cause obstruction of cerebral blood flow and tissue hypoxia/ischemia as a consequence. In the present study, we examined temporal and topographic changes of tissue hypoxia/ischemia after occlusion of the middle cerebral artery (MCA) for 60 min in rats with immunohistochemical staining for hypoxia (2-nitroimidazole hypoxia marker: hypoxyprobe-1 adducts). Our results showed that tissue hypoxia expressed as positive staining for hypoxyprobe-1 adducts preceded neuronal degeneration. Platelets and granulocytes were detected close to the hypoxyprobe-1 adducts positive area. These results suggested that the hypoxic environment could persist even after reperfusion of MCA, because of vascular obstruction with accumulation of platelets and granulocytes.

Erythropoietin-producing cells in the liver of ICR-derived glomerulonephritis (ICGN) mice

The ICR-derived glomerulonephritis (ICGN) mouse is an appropriate model for anemia associated with chronic renal disorder (CRD). Insufficient renal production of erythropoietin (EPO) induces the anemia associated with CRD. EPO mRNA is expressed in both kidneys and liver of progressing-stage ICGN mice. Hypoxic stimulation induced the EPO mRNA expression in the liver as well as in the kidneys of ICGN mice. The localization of EPO-producing cells in the liver remains controversial. Present study using an amplified in situ hybridization technique identified that nonparenchymal cells were the source of hepatic EPO production in ICGN mice under both normoxia and hypoxia.

The initiator caspase, caspase-10β, and the BH-3-only molecule, Bid, demonstrate evolutionary conservation inXenopusof their pro-apoptotic activities in the extrinsic and intrinsic pathways

Two major apoptotic signaling pathways have been defined in mammals, the extrinsic pathway, initiated by ligation of death receptors, and the intrinsic pathway, triggered by cytochrome c release from mitochondria. Here, we identified and characterized the Xenopus homologs of caspase-10 (xCaspase-10beta), a novel initiator caspase, and Bid (xBid), a BH3-only molecule of the Bcl-2 family involved in both the extrinsic and intrinsic pathways. Exogenous expression of these molecules induced apoptosis of mammalian cells. By biochemical and cytological analyses, we clarified that xCaspase-10beta and xBid exhibit structural and functional similarities to their mammalian orthologues. We also detected xCaspase-10beta and xBid transcripts during embryogenesis by whole-mount in situ hybridization and RT-PCR analysis. Microinjection of mRNA encoding a protease-defect xCaspase-10beta mutant into embryos resulted in irregular development. Enforced expression of active xBid induced cell death in developing embryos. Using transgenic frogs established to allow monitoring of caspase activation in vivo, we confirmed that this form of cell death is caspase-dependent apoptosis. Thus, we demonstrated that the machinery governing the extrinsic and intrinsic apoptotic pathways are already established in Xenopus embryos. Additionally, we propose that the functions of the initiator caspase and BH3-only molecule are evolutionarily conserved in vertebrates, functioning during embryonic development.

Production of infectious hepatitis C virus particles in three-dimensional cultures of the cell line carrying the genome-length dicistronic viral RNA of genotype 1b

We show that a dicistronic hepatitis C virus (HCV) genome of genotype 1b supports the production and secretion of infectious HCV particles in two independent three-dimensional (3D) culture systems, the radial-flow bioreactor and the thermoreversible gelation polymer (TGP), but not in monolayer cultures. Immunoreactive enveloped particles, which are 50-60 nm in diameter and are surrounded by membrane-like structures, are observed in the culture medium as well as at the endoplasmic reticulum membranes and in dilated cytoplasmic cisternae in spheroids of Huh-7 cells. Infection of HCV particles is neutralized by anti-E2 antibody or patient sera that interfere with E2 binding to human cells. Finally, the utility of the 3D-TGP culture system for the evaluation of antiviral drugs is shown. We conclude that the replicon-based 3D culture system allows the production of infectious HCV particles. This system is a valuable tool in studies of HCV morphogenesis in a natural host cell environment.

The usefulness of transabdominal ultrasound for the diagnosis of lower gastrointestinal bleeding

BACKGROUND

Lower gastrointestinal bleeding is a frequent cause of hospitalization, but diagnostic methods for this condition are not fully established. Transabdominal ultrasound is a widely accepted diagnostic tool in bowel diseases.

AIM

To evaluate the usefulness of transabdominal ultrasound for lower gastrointestinal bleeding.

METHODS

We reviewed the medical records of consecutive patients who underwent transabdominal ultrasound as the first diagnostic procedure for acute haematochezia during the period June 1999 to June 2004. The study group comprised 111 patients and all underwent colonoscopy thereafter. Detection and diagnosis of lower gastrointestinal bleeding by ultrasonographic examination were evaluated by comparing the ultrasound diagnosis with the colonoscopic findings and final diagnosis.

RESULTS

The bleeding site was localized by colonoscopy in 90 of the 111 patients (81%). The bleeding site was localized by ultrasound in 59 of the 90 patients (66%). When the bleeding site was in the rectum, ultrasonographic detectability was 30% (10/33); ultrasonographic detectability was 82-100% when the bleeding site was elsewhere. Rectal bleeding and diverticular bleeding were difficult to diagnose by ultrasound, but for the other diseases, diagnosis by ultrasonographic examination was possible in 91-100% of cases.

CONCLUSIONS

Ultrasonographic examination may be an effective screening method for lower gastrointestinal bleeding.

The Regulation of Ovarian Granulosa Cell Death by Pro- and Anti-apoptotic Molecules

In the mammalian ovary, follicular development and atresia are closely regulated by cell death and survival-promoting factors, including hormones (gonadotropins) and intraovarian regulators (gonadal steroids, cytokines, and intracellular proteins). Several hundred thousand primordial follicles are present in the mammalian ovary; however, only a limited number of primordial follicles develop to the preovulatory stage and ovulate. The others, more than 99% of follicles, will be eliminated via a degenerative process known as "atresia". The endocrinological regulatory mechanisms involved in follicular development and atresia have been characterized to a large extent, but the precise temporal and molecular mechanisms involved in the regulation of these events have remained largely unknown. Recent studies suggest that the apoptosis of ovarian granulosa cells plays a major role in follicular atresia. In this review, we provide an overview of development and atresia of follicles, and apoptosis of granulosa cells in mammals.

Expression and Localization of Fas Ligand and Fas During Atresia in Porcine Ovarian Follicles

To reveal the mechanisms regulating the selective atresia of follicles in porcine ovaries, we examined the changes in the mRNA and protein levels of cell-death ligand, Fas/APO-1/CD95 ligand (FasL), and its receptor, Fas/APO-1/CD95 (Fas), and the localization of the proteins in granulosa cells during follicular atresia using the reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical techniques, respectively. Trace levels of FasL mRNA and protein were detected in the granulosa cells of healthy follicles; however, weak levels were detected in those of early atretic follicles, and the levels increased during atresia. Trace/weak levels of Fas mRNA and protein were detected in the granulosa cells of healthy follicles. Fas protein was located in the cytoplasmic area, not in cell membrane area, indicating that it has no activity in regard to inducing apoptosis. When apoptosis commences in granulosa cells, Fas moves from the cytoplasmic to cell membrane area. FasL and Fas mRNAs and proteins in granulosa cells were upregulated during follicular atresia. The FasL and Fas system may play a crucial role in the regulation of apoptosis in granulosa cells during selective follicular atresia in porcine ovaries.

Genetic Characteristics of Inbred Wuzhishan Miniature Pigs, a Native Chinese Breed

The Wuzhishan miniature pig originates from Hainan Island, P. R. China, and is considered useful for medical and veterinary research due to its small size; a mature adult weights less than 25 kg. To reveal the genetic characteristics of this breed, the genetic polymorphism in 4 inbred strains was estimated using 30 microsatellite genes, multiplex polymerase chain reaction, and gene scanning. The average number of alleles at the 30 marker loci was 8.300, 4.533, 6.700, and 7.433, respectively. The polymorphism information content was 0.632, 0.507, 0.653, and 0.691, respectively. The average homozygosity in these strains was 0.537, 0.546, 0.549, and 0.520, respectively. These results indicate a relatively high degree of heterozygosity, perhaps becaquse these strains were inbred for 3 generations. Therefore, a long-term inbred breeding program should be conducted for Wuzhishan pigs to establish an experimental model.

Experimental Evidence for the Influence of Cumulus-Oocyte-Complexes on Sperm Release from the Porcine Oviductal Sperm Reservoir

In the pig, a temporal relationship is suggested between sperm release from the sperm reservoir (SR) and ovulation, but the mechanism(s) is still under discussion. In two experiments, the influence of transferred ova on the release of SR-spermatozoa at ovulation and the effect of supplementation with non-sulfated glycosaminoglycan hyaluronan (HA) on embryo development and the number of accessory spermatozoa, respectively, were examined. PMSG/hCG primed ovectomized gilts that had previously received endoscopic low-dose insemination into the cranial uterine horn were used as an experimental model. After salpingectomy, tubal segments (ampulla, cranial, and caudal isthmus) were flushed and sperm numbers or respective accessory spermatozoa were counted. In Experiment 1, the distribution of the sperm population was altered in the presence of cumulus-oocyte-complexes (COCs). A higher proportion of spermatozoa was found after transfer of COCs into one oviduct in the ampulla and cranial isthmus segments compared with the controls (17.5 vs. 4.9%, p<0.05). In Experiment 2, the quality of the transferred ova and treatment influenced the presence of accessory spermatozoa. Transfer of COCs together with HA increased (p<0.05) the number of accessory spermatozoa compared with the other treatment groups and was similar to those in the "undisturbed" controls. No modifications were obtained regarding mean blastomere numbers (2.6 +/- 0.2 to 3.1 +/- 0.2). In summary, this study was demonstrated that cumulus-oocyte-complexes may be involved in triggering sperm release from the pig oviductal SR and that HA might be related to sperm release.

Growth and maturation of follicles and oocytes following xenotransplantation of porcine ovarian tissues and in vitro maturation

This is the first report to show morphological evidence of in vitro maturation of oocytes recovered from xenotransplanted antral follicles. To develop a suitable tool for studing the growth and maturation of follicles and oocytes, we xenotransplanted small pieces of ovarian cortical tissue from sows, which contained small preantral follicles (primordial, primary, and secondary follicles; less than 0.05, 0.1 and 0.3 mm in diameter, respectively), under the capsules of kidneys of adult female severe combined immunodeficient (SCID) mice for 2 and 8 weeks, and then recovered cumulus-oocyte complexes from the growing tertiary follicles in xenografted tissues. The distribution of processes from cumulus cells to oocytes and the follicular growth, development, and maturation during xenotransplantation were histochemically analyzed. Tertiary follicles, 0.5 to 3.0 mm in diameter, were obtained from grafted tissues 2 (85%: 52 follicles/61 grafted tissues) and 8 (50%: 15/30) weeks after xenotransplantation, and then oocytes, which were tightly attached to cumulus cells, were collected from each tertiary follicle and cultured to assess their quality. At 2 weeks after grafting, 17.6% of the oocytes had matured to the metaphase II stage, but no such maturation was observed 8 weeks after grafting. Thus, in the 2 weeks group, preantral follicles rapidly grew in xenotransplanted porcine ovarian tissues to the tertiary stage, and oocytes could be recovered and matured from them by in vitro culture.

Transforming growth factor-β1 mediated up-regulation of lysyl oxidase in the kidneys of hereditary nephrotic mouse with chronic renal fibrosis

Lysyl oxidase (LOX), an extracellular enzyme, plays a key role in the post-translational modification of collagens and elastin, catalyzing inter- and intra-crosslinking reactions. Because the crosslinked extracellular matrices (ECMs) are highly resistant to degradative enzymes, it is considered that the over-expression of LOX may cause severe fibrotic degeneration. In the present study, we addressed the role of LOX-mediated crosslinking in chronic renal tubulointerstitial fibrosis using an animal model of hereditary nephrotic syndrome, the Institute of Cancer Research (ICR)-derived glomerulonephritis (ICGN) mouse. Ribonuclease protection assay (RPA) revealed that LOX mRNA expression was up-regulated in the kidneys of ICGN mice as compared with control ICR mice. High-level expression of LOX and transforming growth factor (TGF)-beta1 (an up-regulator of LOX) mRNA was detected in tubular epithelial cells of ICGN mouse kidneys by in situ hybridization. Type-I and -III collagens, major substrates for LOX, were accumulated in tubulointerstitium of ICGN mouse kidneys. The present findings imply that TGF-beta1 up-regulates the production of LOX in tubular epithelial cells of ICGN mouse kidneys, and the excessive LOX acts on interstitial collagens and catalyzes crosslinking reactions. As a result, the highly crosslinked collagens induce an irreversible progression of chronic renal tubulointerstitial fibrosis in the kidneys of ICGN mice.