Aged and induced-premature ovarian failure mouse models affect diestrus profile and ovarian features.

Sex hormones exert a wide influence on several systems of the human body, especially in women, who undergo intense changes in the trans and postmenopausal periods. Different experimental models are used to mimic these conditions; however, the impact on hormonal profile may be different. This study aimed to analyze and compare vaginal cytology of different post-estropausal mice models, along with their microscopical ovarian features. Forty-six C57BL/6J female mice with the ages of 4, 6 and 18 months at the beginning of the experiment, weighing about 25-28 grams, constituted five groups: NC-(negative control) animals with no treatment, OVX-SHAM-sham ovariectomized, OVX-ovariectomized, VCD-medicated with 160 mg/kg/day of 4-vinylcyclohexene diepoxide via IP for 20 consecutive days, and Aged-senescent mice under physiological estropause. Euthanasia was performed at different periods for the removal of the ovaries, and after diestrus was confirmed by vaginal cytology for 10 consecutive days. For daily vaginal cytology, morphological and histomorphometric microscopic analyzes were performed. Aged mice presented significant increased neutrophils when compared to VCD group, as well as increased cornified epithelial cells when compared to OVX mice, and also increased nucleated epithelial cells when compared to VCD and OVX. NC and OVX-SHAM ovaries presented innumerous follicles at different stages of development, while VCD showed marked follicular atresia, depleted of primordial or developing follicles and a predominance of interstitial cells. The ovaries of aged mice were predominantly constituted by corpus luteum degenerated into corpus albicans, with rare antral follicles. All analyzed models led to different permanent diestrus profiles caused by each model, as indicated by ovarian features. This should be carefully considered when choosing a post-estropausal experimental model, in order to better correlate this challenging phase of female's life with physiological/pathological conditions.

A Putative Role of Teneurin-2 and Its Related Proteins in Astrocytes.

Teneurins are type II transmembrane proteins comprised of four phylogenetically conserved homologs (Ten-1-4) that are highly expressed during neurogenesis. An additional bioactive peptide named teneurin C-terminal-associated peptide (TCAP-1-4) is present at the carboxyl terminal of teneurins. The possible correlation between the Ten/TCAP system and brain injuries has not been explored yet. Thus, this study examined the expression of these proteins in the cerebral cortex after mechanical brain injury. Adult rats were subjected to cerebral cortex injury by needle-insertion lesion and sacrificed at various time points. This was followed by analysis of the lesion area by immunohistochemistry and conventional RT-PCR techniques. Control animals (no brain injury) showed only discrete Ten-2-like immunoreactive pyramidal neurons in the cerebral cortex. In contrast, Ten-2 immunoreactivity was significantly up-regulated in the reactive astrocytes in all brain-injured groups (p < 0.0001) when compared to the control group. Interestingly, reactive astrocytes also showed intense immunoreactivity to LPHN-1, an endogenous receptor for the Ten-2 splice variant named Lasso. Semi-quantitative analysis of Ten-2 and TCAP-2 expression revealed significant increases of both at 48 h, 3 days and 5 days (p < 0.0001) after brain injury compared to the remaining groups. Immortalized cerebellar astrocytes were also evaluated for Ten/TCAP expression and intracellular calcium signaling by fluorescence microscopy after TCAP-1 treatment. Immortalized astrocytes expressed additional Ten/TCAP homologs and exhibited significant increases in intracellular calcium concentrations after TCAP-1 treatment. This study is the first to demonstrate that Ten-2/TCAP-2 and LPHN-1 are upregulated in reactive astrocytes after a mechanical brain injury. Immortalized cerebellar astrocytes expressed Ten/TCAP homologs and TCAP-1 treatment stimulated intracellular calcium signaling. These findings disclose a new functional role of the Ten/TCAP system in astrocytes during tissue repair of the CNS.

Alveolar bone healing in rats: micro-CT, immunohistochemical and molecular analysis.

INTRODUCTION: Alveolar bone healing after upper incisor extraction in rats is a classical model of preclinical studies. The underlying morphometric, cellular and molecular mechanism, however, remains imprecise in a unique study. OBJECTIVES: The aim of this study was therefore to characterize the alveolar bone healing after upper incisor extraction in rats by micro computed tomographic (Micro-CT), immunohistochemical and real-time polymerase chain reaction (RT-PCR) analysis. MATERIAL AND METHODS: Thirty animals (Rattus norvegicus, Albinus Wistar) were divided into three groups after upper incisors extraction at 7, 14, and 28 days. Micro-CT was evaluated based on the morphometric parameters. Subsequently, the histological analyses and immunostaining of osteoprotegerin (OPG), receptor activator of nuclear kappa B ligand (RANKL) and tartrate resistant acid phosphate (TRAP) was performed. In addition, RT-PCR analyses of OPG, RANKL, the runt-related transcription factor 2 (RUNX2), osteocalcin (OC), osteopontin (OPN), osterix (OST) and receptor activator of nuclear kappa B (RANK) were performed to determine the expression of these proteins in the alveolar bone healing. RESULTS: Micro-CT: The morphometric parameters of bone volume and trabecular thickness progressively increased over time. Consequently, a gradual decrease in trabecular separation, trabecular space and total bone porosity was observed. Immunohistochemical: There were no differences statistically significant between the positive labeling for OPG, RANKL and TRAP in the different periods. RT-PCR: At 28 days, there was a significant increase in OPG expression, while RANKL expression and the RANKL/OPG ratio both decreased over time. CONCLUSION: Micro-CT showed the newly formed bone had favorable morphometric characteristics of quality and quantity. Beyond the RUNX2, OC, OPN, OST, and RANK proteins expressed in the alveolar bone healing, OPG and RANKL activity showed to be essential for activation of basic multicellular units during the alveolar bone healing.

Aged rats under zoledronic acid therapy and oral surgery.

INTRODUCTION: Aging brings a number of health conditions that can compromise the healing process in elderly individuals, significantly when it comes to bone tissue. The aim of the present study was to analyze the effects of zoledronic acid (ZL) therapy on socket healing of aged male rats. MATERIALS AND METHODS: Twenty-four Wistar male rats, 20 months old, underwent surgical procedures for the extraction of the upper right incisor and were divided into two groups according to the treatment: Control (C) - intravenous (IV) 0.9% saline, ZL - 0.035 mg/kg of IV zoledronic acid, both every 15 days. At the fifth dose of both substances, tooth extractions were performed and the animals were euthanized after 14 and 28 days. RESULTS: IV administration of ZL caused OPG-RANKL system imbalance, resulting in deficient bone formation and remodeling and alteration of osteoclast morphology, as well as maintaining persistent inflammation during the healing period. CONCLUSIONS: IV administration of ZL delayed extracted dental socket healing of aged rats, but not enough to cause osteonecrosis, raising a question about different responses to IV BP therapy considering animal age.

Kinetics of gene expression of alkaline phosphatase during healing of alveolar bone in rats.

Immunohistochemical studies and molecular biology have enabled us to identify numerous proteins that are involved in the metabolism of bone, and their encoding genes. Among these is alkaline phosphatase (ALP), an enzyme that is responsible for the initiation of mineralisation of the extracellular matrix during alveolar bone repair. To evaluate the gene expression of ALP during this process, we studied nine healthy adult male rats, which had their maxillary central incisors extracted from the right side and were randomly divided into three groups. During three experimental periods, 7 days, 14 days, and 28 days, the alveoli were curetted, the rats killed, and samples analysed by real-time reverse transcription polymerase chain reaction (qRT-PCR). The RNAm that encodes the gene for the synthesis of ALP was expressed during the three periods analysed, but its concentration was significantly increased at 14 and 28 days compared with at 7 days. There was no significant difference between 14 and 28 days (p=0.0005). We conclude that genes related to ALP are expressed throughout the healing process and more intensively during the later periods (14 and 28 days), which coincides with the increased formation of mineralised bone.

Telomeres on chromosome 21 and aging in lymphocytes and gingival fibroblasts from individuals with Down syndrome.

Progressive chromosome 21 loss in individuals with trisomy 21 or Down syndrome (DS) is supposedly related to their premature senescence. In addition, the telomere hypothesis of cellular aging involving telomere shortening in normal and accelerated aging in vivo and in vitro is well documented. This study investigated the integrity of two chromosome 21 regions (the 21q telomere and the 21q22.13-q22.2 region) and their relationship with aging by means of fluorescence in situ hybridization (FISH) in lymphocytes and gingival fibroblasts cells. The use of tissues from different germ layers allows detection of mosaicism. Chromosome variations in tissue from the neuroectoderm layer could explain the variable phenotype of DS. This approach is original in the literature. Lymphocyte and gingival fibroblast nuclei from 18 affected individuals aged 5-54 years were analyzed. Although not significant (P = 0.06), analysis from 11 tissue-matched individuals as well as the comparison between lymphocytes and fibroblasts from different subjects (P = 0.05) suggested that lymphocyte cells are more likely to miss 21q telomere signals. Hence, gingival fibroblasts are probably capable of more efficient cell repair, and the occurrence of mosaicism is more related to cell proliferation than to germ layer origin. Investigation of the 21q22.13-q22.2 region from six tissue-matched individuals and from different DS patients revealed no significant differences between the tissues.

Alveolar bone healing in rats: micro-CT, immunohistochemical and molecular analysis

Abstract Alveolar bone healing after upper incisor extraction in rats is a classical model of preclinical studies. The underlying morphometric, cellular and molecular mechanism, however, remains imprecise in a unique study. Objectives The aim of this study was therefore to characterize the alveolar bone healing after upper incisor extraction in rats by micro computed tomographic (Micro-CT), immunohistochemical and real-time polymerase chain reaction (RT-PCR) analysis. Material and Methods Thirty animals (Rattus norvegicus, Albinus Wistar) were divided into three groups after upper incisors extraction at 7, 14, and 28 days. Micro-CT was evaluated based on the morphometric parameters. Subsequently, the histological analyses and immunostaining of osteoprotegerin (OPG), receptor activator of nuclear kappa B ligand (RANKL) and tartrate resistant acid phosphate (TRAP) was performed. In addition, RT-PCR analyses of OPG, RANKL, the runt-related transcription factor 2 (RUNX2), osteocalcin (OC), osteopontin (OPN), osterix (OST) and receptor activator of nuclear kappa B (RANK) were performed to determine the expression of these proteins in the alveolar bone healing. Results Micro-CT: The morphometric parameters of bone volume and trabecular thickness progressively increased over time. Consequently, a gradual decrease in trabecular separation, trabecular space and total bone porosity was observed. Immunohistochemical: There were no differences statistically significant between the positive labeling for OPG, RANKL and TRAP in the different periods. RT-PCR: At 28 days, there was a significant increase in OPG expression, while RANKL expression and the RANKL/OPG ratio both decreased over time. Conclusion Micro-CT showed the newly formed bone had favorable morphometric characteristics of quality and quantity. Beyond the RUNX2, OC, OPN, OST, and RANK proteins expressed in the alveolar bone healing, OPG and RANKL activity showed to be essential for activation of basic multicellular units during the alveolar bone healing.

Influência do ácido nicotínico ministrado na dieta e por intubagem gástrica sobre a incidência de cárie em ratos submetidos à dieta cariogênica e à ração de laboratório / The influence of nicotinic acid administered in the diet or by gastric intubation on the incidence of dental caries in rats submitted to cariogenic diet and laboratory chow

Foi estudado o efeito do ácido nicotínico ministrado na dieta e por intubagem gástrica sobre a incidência de cárie em ratos submetidos à dieta cariogênica e à ração de laboratório. Ratos que receberam ácido nicotínico misturado na dieta cariogênica ou na ração normal sofreram um aumento na incidência de cárie, porém não estatisticamente significante da dos controles sem tratamento. Por outro lado, ratos que receberam ácido nicotínico por intubagem gástrica apresentaram uma diminuição na incidência de cárie, estatisticamente significante com relação aos seus controles, sem tratamento. Os resultados demonstram que o ácido nicotínico teve uma atuação sistêmica sobre a incidência de cárie, porém a razão pela qual esta vitamina diminuiu a incidência de cárie ainda não é conhecida