Histochemistry and Cell Biology最新文献

Diabetes mellitus (DM) is characterized by the loss or dysfunction pancreatic β-cells. Human amniotic epithelial cells (hAEC), which retain pluripotency markers and are readily obtainable from term placentas, represent a promising alternative source of stem cells. We investigated whether hAECs can be guided through pancreatic ontogeny to generate insulin-producing β-like cells. hAEC from uncomplicated term deliveries were expanded to passage 1 and exposed to a four-stage differentiation sequence that sequentially modulated Activin/WNT, KGF/TGF-β, retinoic-acid/hedgehog, and EGF/Noggin signaling. Stage progression was monitored by end-point RT-PCR and quantitative immunofluorescence for hallmark transcription factors. After definitive endoderm induction, 64% of cells were Brachyury positive and 71% were WNT3A positive; primitive-gut specification yielded 57% HNF1B⁺ cells. Posterior foregut commitment produced 75% PDX1⁺ and 60% Sox9⁺ nuclei and the final endocrine stage generated 74% NKX2.2⁺ cells, with 71% showing cytoplasmatic insulin and 51% C-peptide staining; insulin/C-peptide co-localization was confirmed by double labelling. Thus a chemically defined, four-step protocol can convert term-derived hAEC into insulin-producing β-like cells, supporting their use as an accessible platform for diabetes modelling and future cell-replacement therapies.

Ovarian hyperstimulation syndrome (OHSS) is the most severe complication of ovarian stimulation during assisted reproductive procedures and resembles an acute inflammatory response. Curcumin possesses antioxidant, anti-inflammatory, and anti-angiogenic properties. However, its impact on OHSS remains unclear. This study aimed to investigate the protective effects of curcumin in a rat model of OHSS and elucidate its underlying mechanisms. A rat model of OHSS was established using gonadotropin and human chorionic gonadotropin (hCG), followed by 7 days of curcumin administration. Pathological changes in ovarian tissue were assessed via hematoxylin and eosin (H&E) staining. The expression levels of serum estradiol (E₂), vascular endothelial growth factor (VEGF), VEGF-receptor 2 (VEGFR2), and inflammatory factors were measured using enzyme-linked immunosorbent assay (ELISA). Additionally, malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels were assessed using commercial kits. Finally, nuclear factor kappa B (NF-κB) and hypoxia-inducible factor 1-alpha (HIF-1α) levels in ovarian tissue were analyzed using western blotting. The results showed that curcumin significantly alleviated ovarian tissue pathological damage in rats with OHSS and reduced the serum levels of E₂, VEGF, VEGFR2, interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α). Additionally, SOD and GSH-Px levels were significantly elevated, while MDA levels were significantly diminished. Moreover, curcumin significantly inhibited NF-κB activation, downregulated HIF-1α expression, and consequently reduced VEGF expression. In summary, curcumin reduced VEGF levels by inhibiting the NF-κB/HIF-1α signaling pathway, thereby alleviating symptoms of gonadotropin-induced OHSS. It may serve as a potential therapeutic agent for OHSS prevention and treatment.

Nesfatin-1, identified as an anorexigenic neuropeptide in the hypothalamus, is activated by glutamatergic agonists and innervated by excitatory and inhibitory neurons. The uridine nucleotide uridine diphosphate was recently identified as a novel regulator of feeding-related neurons. However, the activating effects of uridine and uridine nucleotides on anorexigenic NUCB2/nesfatin-1 neurons are unknown. In this study, the activating effects of intracerebroventricularly administered uridine or uridine nucleotides (UMP, UDP, UTP) on NUCB2/nesfatin-1 neurons localized in the supraoptic (SON), paraventricular (PVN), and periventricular (PeV) nuclei were determined using c-Fos immunohistochemistry. Results were evaluated as the percentage of the ratio of c-Fos-expressing (activated) NUCB2/nesfatin-1 neurons to all NUCB2/nesfatin-1 neurons. It was determined that centrally administered uridine, UMP, and UTP activated a statistically significant number of NUCB2/nesfatin-1 neurons in the SON, PVN, and PeV, compared with the saline group (p < 0.05). At the same time, the slight increase in the neuronal activation seen following UDP application was not found to be significant. The results of this study show that NUCB2/nesfatin-1 neurons respond to uridine and uridine nucleotides in the form of neuronal activation, possibly through pyrimidinergic neurotransmission.

This study investigated the effects of an experimentally induced hyperthyroidism model on the pituitary-ovarian axis and the possible protective role of vitamin E against these adverse effects. Wistar albino rats were divided into five groups of eight animals each: control ("Cont," no any treatment); hyperthyroidism ("Hypert," L-thyroxine at 0.3 mg/kg/day); "Sham" (1 ml/day corn oil); "Hypert + vit E" (L-thyroxine (0.3 mg/kg/day and 100 mg/kg/day/1 ml vitamin E); and "Vit E" (100 mg/kg/day/1 ml vitamin E) groups. At the end of the experiment, ovarian tissues were exposed to electron microscopic and stereological analyses. Thyroid stimulating hormone (TSH), free thyroxine (FT4), follicle stimulating hormone (FSH), luteinizing hormone (LH), and superoxide dismutase (SOD) levels, as well as catalase (CAT) enzyme activity, were also determined in blood serum samples. Ovarian follicle numbers and volumes; corpus luteum and cortex volume; body weights; and TSH, FSH, and SOD levels decreased significantly in the Hypert group compared with the Cont group. However, connective tissue volume, CAT enzyme activity, and FT4 levels increased in the Hypert group compared with the Cont group. Vitamin E supplementation was observed to play a protective role on antral follicle, corpus luteum, and connective tissue volumes, CAT activity, and SOD and FSH levels. Hyperthyroidism reduces the number of ovarian follicles and may cause infertility problems. The adverse effect of hyperthyroidism on the pituitary-ovarian axis can be ameliorated by means of vitamin E, since this may have a homeostatic effect on this axis, as shown by the biochemical, histopathological, and stereological analyses in this study.

A growing body of evidence indicates that the endocannabinoid system (ECS) is essential for controlling the homeostasis of the skin and that the ECS is modified in the presence of skin disease. It is plausible to expect that the lamellar junction of the hoof expresses cannabinoid receptors and that their expression could be affected by lamellar disease. The goal of this study was to characterise the cannabinoid receptor type 1 (CB1R) and type 2 (CB2R) and the G protein-coupled receptor 55 (GPR55) within the dermo-epidermal junction of the hooves of healthy and laminitic horses. The expression of the CB1R, CB2R, and GPR55 within the dermo-epidermal lamellar junction of six healthy and 12 laminitic hooves was studied using polymerase chain reaction (PCR) and immunofluorescence. Both the mRNA and protein expression of the CB1R, CB2R, and GPR55 were found in the dermo-epidermal lamellar junction of horse hooves. The immunolabelling was expressed by the epithelial cells of the primary and secondary laminae of healthy hooves (CB2R > GPR55 > CB1R). The presence of CB1R, CB2R, and GPR55 immunoreactivity in the healthy laminar epithelial cells, coupled with increased protein expression in pathological epithelial cells, provided strong motivation for future investigation. These findings suggest that cannabinoid compounds which interact with these receptors may influence lamellar healing and mitigate inflammation in hoof diseases, particularly laminitis.

The success of both oogenesis and early embryo development relies heavily on dynamic epigenetic regulation in which gene activity changes without affecting the underlying DNA sequence. Epigenetics works through two main mechanisms: DNA methylation and histone modifications. DNA methylation typically leads to gene silencing, while histone modifications can either activate or repress genes depending on the specific modification, histone type, and targeted amino acid residue. Histone modifications affect important DNA regulatory processes in which the histone core area as well as the N-terminal tails that extend from the core region are vulnerable to a variety of posttranslational modifications (PTMs), including methylation, citrullination (deimination), acetylation, phosphorylation, ubiquitination, SUMOylation, ribosylation, and lactylation. This review article focuses on what is known about changes in the histone modifications and how these modifications and their responsible enzymes operate throughout mammalian oocyte maturation and early embryo development, highlighting their crucial roles in these processes.

The use of oxalic acid is common in metallic impregnation techniques, where it serves as a reducing and bleaching agent for potassium permanganate. Given that oxalic acid is harmful to health, its replacement with another reagent is advantageous for healthcare professionals handling it in laboratory settings. Considering that citric acid can also reduce potassium permanganate, the aim of this study was to determine whether oxalic acid in the Gomori reticulin technique could be replaced by citric acid, a compound substantially less hazardous to health. To this end, 1%, 5%, and 10% citric acid solutions were tested on porcine liver and kidney samples, and the intensity of reticulin fiber staining, contrast, and overall morphological preservation were assessed in comparison with 1% oxalic acid. The results showed no statistically significant differences between the positive control (oxalic acid) and the citric acid protocols, with the 5% citric acid concentration proving most favorable in terms of required incubation time and the evaluated morphological parameters. It was therefore concluded that citric acid can be used as a bleaching agent for potassium permanganate in the Gomori technique, effectively replacing oxalic acid.

Joint-related diseases often involve multiple aspects of angiogenesis, alterations in the extracellular matrix (ECM), and inflammatory responses, causing pain and mobility problems for patients. Angiopoietins (Angs) are a protein family of secreted growth factors that have a variety of functions, including regulating angiogenesis, stabilizing blood vessels, and mediating changes in the ECM. The first Ang was discovered by Davis in COS cells, and since then, three more members of this protein family have been discovered. Among these four members, Ang-1 and Ang-2 play the most essential roles in joint diseases and are closely related to each other as ligands for the Tie-2 receptor. Ang-1 acts as an agonist at the Tie-2 receptor, while Ang-2 can act as either an agonist or antagonist of Tie-2 under specific conditions. This review describes the structure and general physiological functions of Angs and summarizes the role of Angs in joint-related diseases. It concludes with possible Ang-based therapeutic strategies.

Super-resolution radial fluctuation (SRRF) microscopy is a novel computational imaging technique that bypasses the optical diffraction limit (lateral resolutions of 200-300 nm), achieving lateral resolutions of approximately 50-100 nm while being compatible with live-cell imaging. Unlike traditional super-resolution methods such as stimulated emission depletion (STED) and single molecule localization microscopy (SMLM), SRRF minimizes phototoxicity and hardware complexity by analyzing fluorescence intensity fluctuations in standard wide-field microscopy data. This is achieved by calculating local gradient convergence ("radiality") across time-series images, enabling the reconstruction of sub-diffraction structures without specialized fluorophores or high-intensity illumination. Implemented through the open-source NanoJ-SRRF platform, SRRF optimizes parameters like ring radius and radiality magnification to enhance resolution, suppress noise, and maintain computational efficiency. Its advantages include low phototoxicity, compatibility with conventional dyes, and integration with various imaging modalities, allowing dynamic visualization of subcellular processes (e.g., mitochondrial fission, microtubule dynamics). Despite its limitations in axial resolution and potential artifacts in high-density structures, recent advancements like enhanced SRRF (eSRRF) and variance reweighted radial fluctuations and enhanced SRRF (VeSRRF) address these challenges, facilitating real-time, multicolor imaging. Applications range from ultrastructural studies to clinical pathology, with future developments in AI processing and multimodal integration promising further enhancements in imaging capabilities. SRRF stands to significantly impact the understanding of dynamic subcellular processes and biomedical research.