Changes of colon epithelium proliferation due to individual aging with cyclin proliferating cell nuclear antigen (PCNA/cyclin) immunostaining compared to [3H]-thymidine radioautography

Cell Aging of Mouse Gastrointestinal Tract Observed by Light and Electron Microscopic Radioautography

The term "cell aging" initially means how the cells change due to their aging. There are two meanings, i.e. how a cell changes when it is isolated from original animals such as in vitro cells in cell culture, otherwise how all the cells of an animal change in vivo due to the aging of the individual animal. We have been studying the latter changes from the viewpoint of the cell nutrients, the precursors for the macromolecular synthesis such as deoxyribonucleic acid (DNA), ribonucleic acid (RNA), proteins, glucides and lipids, which are incorporated and synthesized into various cells of individual animals. Therefore, this article deals with only the cell aging of animal cells in vivo, how the metabolism, i.e. incorporations and syntheses of respective nutrient precursors in various kinds of cells change due to the aging of individual experimental animals such as mice by means of microscopic radioautography to localize the RI-labeled precursors. The incorporations and syntheses of various precursors for macromolecules such as DNA, RNA, proteins, glucides, lipids and others in various kinds of cells of various organs in the gastrointestinal tract such as the mouth, esophagus, stomach and intestines are reviewed referring many original papers already published from our laboratory during these 60 years since the late 20th century.

Distribution of tenascin-C and -X and expression of tenascin-C and X mRNA in the postnatal rat tongue

Different distributions of tenascin-C and -X are found in various organs. However, the role of the tenascin family in the process of formation in the papillae epithelium during development is poorly understood. In order to find more information an tenascin-C and -X distributions during tongue development, immunohistocheminical studies have been carried out to demonstrate these distributions. The number of PCNA positive cells gradually increased from 5- to 15-days, and decreased on 21-days in the intercellular space of the epithelal layer in the postnatal development of rat tongue (150 specimens of Wistar male rats (0-, 5-, 10-, 15-, and 21-days). The reaction of tenascin-C was found mainly in the intercellular space of the epithelial layer on contrast to that of tenascin-X which was mainly found an the epithelial layer under a confocal laser scanning microscope. The level of mRNA of tenascin-C (600bp) and tenascin-X (588bp) gradually decreased from 5-days using RT-PCR methods. The different distribution of these extracellular matrices and weakly-regulated expressions may be related to the replication process of the epithelium in the tongue during development.

Proliferating cell nuclear antigen immunoreactivity in the ovarian surface epithelium of mice of varying ages and total lifetime ovulation number following ovulation

Everytime an oocyte is released at ovulation, the ovarian surface epithelium (OSE) is ruptured and must be restored by epithelial cell proliferation. Ovulation site closure was studied in mice of various ages along with total lifetime ovulation number to investigate the known association of these factors with the risk of epithelial ovarian cancer. Ovaries from Swiss Webster mice were collected at various time points postovulation from 3-mo virgin animals (estimated median total lifetime ovulation number, 92; n = 40 mice), 8-mo virgin animals subject to incessant ovulation (estimated median total lifetime ovulation number, 652; n = 15 mice), and 12-mo breeders (estimated median total lifetime ovulation number, 208; n = 35 mice). Diameters of ovulation sites were estimated by scanning electron microscopy. No differences were found in the rate of ovulation site closure between the groups. Sections of ovaries were analyzed using immunohistochemistry for proliferating cell nuclear antigen (PCNA). The highest density of immunoreactive cells was observed in all animal groups in the cuboidal cells around the rupture site the day after ovulation. Despite the similarity in ovulation site closure rates between groups, the total number of OSE cells that were positive for PCNA in both the 8- and 12-mo animals was significantly reduced, so the number of stained cells appeared to be insufficient to cover the ovulation site. These data suggest that other mechanisms, such as proliferation of the extraovarian mesothelium, may play a role in the re-epithelialization of the ovary.

Radioautographology general and special

A new concept, termed "radioautographology" is advocated and its contents are reviewed. This term is the coinage synthesized from "radioautography" and "(o)logy", expressing a new science derived from radioautography. The concept of radioautographology (RAGology) is a science to localize the radioactive substances in the biological structure of the objects and to analyze and to study the significance of these substances in the biological structure. On the other hand, the old term radioautography (RAG) or autoradiography (ARG) is the technique to demonstrate the pattern of localization of various radiolabeled compounds in biological specimens. The specimens used in biology and medicine are cells and tissues. They are fixed, sectioned and made contact with the radioautographic emulsions, exposed and developed to produce metallic silver grains. Such specimens are designated as radioautographs (or autoradiographs) and the patterns of pictures made of silver grains are named radioautograms. Those people who produced radioautographs were formerly named radioautographers (or autoradiographers) who were only technicians, while those who study RAGology are not technicians but scientists and should be called as radioautographologists. The science of radioautographology was developed in the 20th century and can be divided into two parts, general radioautographology and special radioautographology, as most natural sciences usually can. The general radioautographology is the technology of RAG which consists of 3 fields of sciences, physics concerning radioactivity, histochemistry treating the cells and tissues and photochemistry dealing with the photographic emulsions. The special radioautographology, on the other hand, consists of applications of general radioautographology to various biological and medical sciences. The applications can be classified into several scientific fields, i.e., cellular molecular biology, anatomy, histology, embryology, pathology and pharmacology. Studies carried out in our laboratory were summarized and reviewed. The results obtained from the technology includes 4-dimensional structures of the organs taking the time dimension into account by labeling cells and localizing the sites of incorporation, synthesis, discharge of the labeled compounds in connection with the time lapse and aging of animals. All the results obtained from such applications should be systematized as a new filed of science in the future in the 21st century.

Special cytochemistry in cell biology

Cytochemistry is a science of localizing chemical components of cells and organelles on histological sections by using various techniques. We first aimed at studying cytochemistry by developing new techniques using various principles such as enzyme cytochemistry, microincineration, microspectrophotometry, radioautography, cryo-techniques, X-ray microanalysis and immunocytochemistry. We first concentrated on developing methodologies in the 1960s to 1970s. We then applied these special techniques to various kinds of cells in men and animals. Earlier, I proposed to classify these methods into three categories, i.e., chemical, physical, and biological techniques. The methodology has been well developed to form a new science which should be designated as "general cytochemistry" similarly to the general histology. On the other hand, these techniques should be applied to various cells in various organ systems, such as the skeletal, muscular, digestive, respiratory, urinary, reproductive, endocrine, circulatory, nervous and sensory systems similarly to the special histology or the histology of organs. I summarize the results of cytochemical studies on cells of various organs carried out in our laboratory during these 44 years since 1955. The results obtained from cytochemical studies applied to various cells in respective organ systems should be designated as "special cytochemistry."

Apoptosis and cell proliferation potential of bovine embryos stimulated with insulin-like growth factor I during in vitro maturation and culture

Reliable estimation and improvement of the developmental potential of in vitro production (IVP) embryos requires functional criteria of embryo quality. Antiapoptotic and mitogenic effects of insulin-like growth factor I (IGF-I), applied during bovine IVP, were studied. Day 6.5 blastocysts were fixed and processed for TUNEL to detect apoptotic cells, for immunocytochemical detection of proliferating cell nuclear antigen (PCNA), and for propidium iodide (PI) staining to detect all nuclei. Laser scanning confocal microscopy was used to determine apoptotic (TUNEL/PI) and proliferative (PCNA/PI) indices. Addition of IGF-I to the culture but not to the maturation medium increased the morula/blastocyst yield (P = 0.03), but the cleavage rate was not affected. During culture, IGF-I significantly lowered the apoptotic index by decreasing the number of apoptotic cells per embryo and elevated the total cell number of the blastocysts. The frequency of blastocysts with apoptotic cells was not affected. IGF-I increased the proportion of blastocysts with apoptotic cells in the inner cell mass area only by reducing apoptosis in the trophectoderm area. The PCNA index was not affected by IGF-I. A positive correlation observed between apoptotic and PCNA-positive cells was significant in groups stimulated with IGF-I during in vitro culture. Of TUNEL-positive cells, 30%-40% per embryo were also positive for PCNA. This colocalization may indirectly suggest an activation of DNA repair process in TUNEL-positive cells in response to DNA fragmentation. IGF-I reduces apoptosis in bovine IVP embryos. The requirement of IGF-I is more critical during embryo culture than during oocyte maturation. Our data suggest that an assay for TUNEL in conjunction with cell proliferation analysis can provide useful information about the quality of IVP embryos.

Ratio of proliferating cell nuclear antigen-positive nuclei to total cell number is higher in day 7 than in day 8 vitrified in vitro-produced bovine embryos

The aim of the present study was to find a reliable functional criterion for the evaluation of the proliferation potential of bovine in vitro-produced embryos. We used immunocytochemical detection of proliferating cell nuclear antigen (PCNA) combined with propidium iodide (PI) staining and subsequent confocal laser scanning microscopy together with routine morphological evaluation under a stereomicroscope to study fresh Day 7, 8, and 9, and cryopreserved Day 7 and 8 embryos. The ratio of PCNA/PI-positive nuclei was equal in fresh Day 7 and Day 8 embryos and significantly lower in Day 9 embryos. In general, Day 7 embryos tolerated the cryopreservation treatments better than Day 8 embryos. Vitrification in normal straws was especially detrimental to Day 8 embryos. In fresh Day 7 and 8 embryos, the PCNA results were in agreement with stereomicroscopic evaluation. However, in Day 9 fresh and in Day 7 and 8 treated embryos, the missing PCNA revealed disorders that were not observed under morphological evaluation. PCNA immunocytochemistry is an effective method to obtain information about the functional state of nuclei. The ratio of PCNA-positive nuclei can provide more information and numerical data about the developmental potential of bovine embryos after cryopreservation.

Marmoset spermatogenesis: organizational similarities to the human

The common marmoset (Callithrix jacchus), a small New World primate of high fecundity, is widely used in reproductive research. The aim of the present study was to determine the organization of the germ cells within the seminiferous epithelium, the duration of the spermatogenic cycle and the number of spermatogonial mitoses. Antibodies to cAMP response element modulator (CREM) and proliferating nuclear cell antigen (PCNA) and a cRNA directed against protamine P2 and morphological criteria were used to discriminate between stages of the spermatogenic cycle. Plastic sections were used to document the cell associations present in each of the nine stages of spermatogenesis. Up to five such stages could be observed within individual cross-sections of seminiferous tubules. Based on the pattern of incorporation of bromodeoxyuridine the length of the spermatogenic cycle was estimated to be 10 days and the duration of spermatogenesis to be 37 days. Four mitotic divisions were noted in spermatogonia. It is concluded that the organization of spermatogenesis in the marmoset has similarities to the human ('helical') and this makes the marmoset a suitable model for studies relevant to human testicular function.

Proliferating cell nuclear antigen in normal and regenerating rat livers

Immunohistochemical analysis using proliferating cell nuclear antigen (PCNA) antibody shows a negligible number of cells stained in normal liver, but much higher numbers in regenerating liver 24 and 48 h after surgery. We also verified different results by biochemical analysis. Two forms of PCNA, L type (eluted at low concentrations of KCl from a phosphocellulose column) and H type (eluted at high KCl concentrations), were observed in the nucleoplasm of regenerating livers 24 and 48 h after surgery. Treatment of the H type fraction with nuclease caused the H type to disappear and the amount of L type to increase. PCNAs in the cytoplasm are P type (eluted in the pass through fraction) and L type. Surprisingly, the total amounts of P type and L type in cytoplasmic extracts are comparable to those of L type and H type in the nucleoplasm. These results suggest that newly synthesized PCNA is immediately converted into the P and L complex forms. The P type and some of the L type that lacks a nuclear localization signal remain in the cytoplasm; the rest of the L type with a nuclear localization signal is transferred into the nuclei. Then, some of the L type in the nucleoplasm forms the H type, which binds to DNA. These three types of PCNA are also found in significant amounts in the nucleoplasm and cytoplasm of normal rat liver despite its nonproliferating state.

Differing proliferative responses in proximal and distal colons of growing rats fed food eaten by adenoma patients

Animal dietary studies related to human colorectal carcinogenesis are usually based on AIN-76A diet, which is dissimilar to human food in source, preparation, and content. Our aim was to examine colonic epithelial proliferation in rats fed a diet based on the mean daily food intake of adenoma patients. Foods were prepared as reported by the adenoma patients and dehydrated; 64 Sprague-Dawley rats were fed either "human adenoma" or AIN-76A diet and every eight weeks, eight from each group were sacrificed. Both groups gained weight equally, had no colonic histological changes, but during the study showed progressive lengthening of colonic crypts (P < 0.01) and decreased proliferation (P < 0.05) in distal colons. Compared to controls, rats fed human adenoma diet had significantly longer crypts (P < 0.01) and more labeled cells (P < 0.05) at 32 weeks; overall they had increased proliferation (P < 0.01), most significantly in the distal colon. Thus, food eaten by adenoma patients induced hyperproliferative changes in the rat colon during growth and maturity, especially the distal colon, as found in humans at risk for neoplasia.

Expression of nitric oxide synthase in mucosal cells of the canine colon

The expression of nitric oxide synthase (NOS) in the mucosa of the canine colon was investigated with in situ hybridzation, immunohistochemistry (using isoform specific antibodies), western analysis, and NADPH diaphorase (NADPH-d) histochemistry. In situ hybridization using a common probe for known isoforms of NOS showed that NOS mRNA was strongly expressed in mucosal cells. A gradient in the degree of hybridization was noted from the base of the crypts to the luminal surface. This gradient was also apparent using an endothelial NOS (eNOS)-specific probe. Neural NOS-like immunoreactivity (nNOS-LI) was observed in columnar epithelial cells, and the same population of cells was stained with NADPH-d. Endothelial NOS-like immunoreactivity (eNOS-LI) was also found in mucosal cells; however, this eNOS-LI was confined to mucous cells. These cells were not stained with NADPH-d. The existence of eNOS in mucosal cells was confirmed by in situ hybridization using the probe which specifically hybridized with mRNA of eNOS and by western blots which demonstrated the expression of a 135-kDa protein in mucosal homogenates. The differential expression of NOS isoforms and the gradient in expression along the length of the crypts suggest complex roles for NO in the development of colonic epithelial cells and in secretion and transport functions of the colonic mucosa.

Relationship between cellular DNA synthesis, PCNA expression and sex steroid hormone receptor status in the developing mouse ovary, uterus and oviduct

The proliferative activities of the different cellular compartments of the developing mouse ovary, uterus, and oviduct were studied by radioautographic assessment of DNA synthesis with [3H]-thymidine labeling and by immunohistochemical staining of proliferating cell nuclear antigen (PCNA). The distributions of estrogen and progesterone receptors (ER and PR) were studied by immunohistochemical staining. The values of the PCNA positive staining indices were a little higher than that of the radioautographic labeling indices. However, linear relations were shown for the two indices. The proliferative activities were high from postnatal day 1-7 and decreased from day 14 in the different cellular compartments of the ovary. The proliferative activities were high on days 1, 3 and decreased from day 7 in the uterus and oviduct. Staining of ER and PR was very weak in the surface epithelium, stroma and large follicles of the ovary. Positive staining for ER occurred from day 14 in the uterine epithelium and from day 7 in oviductal epithelium. Positive staining for PR was observed from day 1 in both the uterine and oviductal epithelium. However, the positivity of both ER and PR occurred from postnatal day 1 in the stromal cells of the uterus and oviduct. These results suggest that the appearance of the steroid receptors differ between the different cellular compartment of the reproductive organs. The proliferative activities have an inverse relation with the expression of the steroid hormone receptors in the female reproductive organs during developmental stages.(ABSTRACT TRUNCATED AT 250 WORDS)