Exploration of tissue fixation methods suitable for digital pathological studies of the testis.

BACKGROUND: The way of testicular tissue fixation directly affects the correlation and structural integrity between connective tissue and seminiferous tubules, which is essential for the study of male reproductive development. This study aimed to find the optimal fixative and fixation time to produce high-quality testicular histopathological sections, and provided a suitable foundation for in-depth study of male reproductive development with digital pathology technology. METHODS: Testes were removed from both sides of 25 male C57BL/6 mice. Samples were fixed in three different fixatives, 10% neutral buffered formalin (10% NBF), modified Davidson's fluid (mDF), and Bouin's Fluid (BF), for 8, 12, and 24 h, respectively. Hematoxylin and eosin (H&E) staining, periodic acid Schiff-hematoxylin (PAS-h) staining, and immunohistochemistry (IHC) were used to evaluate the testicle morphology, staging of mouse seminiferous tubules, and protein preservation. Aperio ScanScope CS2 panoramic scanning was used to perform quantitative analyses. RESULTS: H&E staining showed 10% NBF resulted in an approximately 15-17% reduction in the thickness of seminiferous epithelium. BF and mDF provided excellent results when staining acrosomes with PAS-h. IHC staining of synaptonemal complexes 3 (Sycp3) was superior in mDF compared to BF-fixed samples. Fixation in mDF and BF improved testis tissue morphology compared to 10% NBF. CONCLUSIONS: Quantitative analysis showed that BF exhibited a very low IHC staining efficiency and revealed that mouse testes fixed for 12 h with mDF, exhibited morphological details, excellent efficiency of PAS-h staining for seminiferous tubule staging, and IHC results. In addition, the morphological damage of testis was prolonged with the duration of fixation time.

Expression profile analysis of LncRNAs and mRNAs in pre-receptive endometrium of women with polycystic ovary syndrome undergoing in vitro fertilization-embryo transfer.

BACKGROUND: To compare the expression levels of long non-coding RNA (lncRNA) and messenger RNA (mRNA) in pre-receptive endometrium between patients with Polycystic Ovary Syndrome (PCOS)and normal ovulation undergoing in vitro fertilization-embryo transfer (IVF-ET). METHODS: Endometrial tissues were collected with endometrial vacuum curette in pre-receptive phase (3 days after oocytes retrieval) from PCOS and control groups. LncRNAs and mRNAs of endometrium were identified via RNA sequencing and alignments. A subset of 9 differentially expressed lncRNAs and 11 mRNAs were validated by quantitative reverse transcription polymerase chain reaction(qRT-PCR)in 22 PCOS patients and 18 ovulation patients. The function of mRNAs with differential expression patterns were explored using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). RESULTS: We found out 687 up-regulated and 680 down-regulated mRNAs, as well as 345 up-regulated and 63 down-regulated lncRNAs in the PCOS patients in contrast to normal ovulation patients. qRT-PCR was used to detect the expression of 11 mRNAs, and validated that the expression of these 6 mRNAs CXCR4, RABL6, OPN3, SYBU, IDH1, NOP10 were significantly elevated among PCOS patients, and the expression of ZEB1 was significantly decreased. qRT-PCR was performed to detect the expression of 9 lncRNAs, and validated that the expression of these 7 lncRNAs IDH1-AS1, PCAT14, FTX, DANCR, PRKCQ-AS1, SNHG8, TPT1-AS1 were significantly enhanced among PCOS patients. Bioinformatics analysis showed that differentially expressed genes (DEGs) involved KEGG pathway were tyrosine metabolism, PI3K-Akt pathway, metabolic pathway, Jak-STAT pathway, pyruvate metabolism, protein processing in endoplasmic reticulum, oxidative phosphorylation and proteasome. The up-regulation of GO classification was involved in ATP metabolic process, oxidative phosphorylation, RNA catabolic process, and down-regulation of GO classification was response to corticosteroid, steroid hormone, and T cell activation. CONCLUSION: Our results determined the characteristics and expression profile of endometrial lncRNAs and mRNAs in PCOS patients in pre-receptive phase, which is the day 3 after oocytes retrival. The possible pathways and related genes of endometrial receptivity disorders were found, and those lncRNAs may be developed as a predictive biomarker of endometrium in pre-receptive phase.

Changes in Expressions of Spermatogenic Marker Genes and Spermatogenic Cell Population Caused by Stress.

Many young adults are in a state of stress due to social and psychological pressures, which may result in male reproductive dysfunction. To provide new insight into this phenomenon, we investigated the effect of stress on the regulation of key genes and biological events in specific stages of spermatogenesis. After establishing rat stress models of different time durations, we observed pathological changes in testis through haematoxylin and eosin staining, and analysed gene expression in testis by RNA-seq, bioinformatic analysis, and reverse transcription qPCR (RT-qPCR). Immunohistochemistry (IHC) with the TissueFAXS quantitative imaging system was used to verify changes of different population of spermatogenic cells marked by differentially expressed marker genes. Our results showed that prolonged stress can lead to pathological changes in the testes, such as thinning of the spermatogenic epithelium, a decreased number of spermatogenic epithelial cells, the disordered arrangement of spermatogenic cells, and a decreased number of mature sperms. RNA-seq revealed that key marker spermatogenesis-related genes such as Stra8, Sycp3, Piwil1, and Tnp1 had significantly decreased expression levels in chronic stress groups, and this was confirmed by RT-qPCR and IHC. Collectively, these findings suggest that chronic stress causes damaging pathological changes in testis and dysregulates the marker genes of specific stages of spermatogenesis and change the population of spermatogenic cells, which may be a critical responsible for male reproductive dysfunction.

A long non-coding RNA specifically expressed in early embryos programs the metabolic balance in adult mice.

Many Long non-coding RNAs (lncRNAs) are specifically expressed in early embryos, but the physiological functions of most of them remain largely unknown. Here, we show that deficiency of lncenc1, an early embryo-specific lncRNA, altering glucose and lipid balance in adult mice. Newly weaned lncenc1-deficient mice prefer to use lipids as a fuel source. When mice were fed a normal chow diet (NCD), glucose intolerance and insulin resistance were observed in adult lncenc1-deficient mice. Under high-fat diet (HFD) conditions, however, lncenc1-deficient mice became healthier and could resist food-induced obesity and metabolic disturbances. Furthermore, AKT/mTOR-regulated lipogenesis in liver was reduced in lncenc1-deficient mice fed a HFD. MEFs lacking lncenc1 showed impaired glycolysis and lipogenesis, suggesting that the metabolic defects may already exist in embryos. Our study demonstrated the essential roles of lncenc1 in adult metabolism, providing experimental data that support the "fetal origin" of adult metabolic disorders.

Chronic stress reduces spermatogenic cell proliferation in rat testis.

Male reproductive dysfunction induced by mental stress and environmental factors has increased greatly in recent years. Previous studies of the male rat reproductive system under stress conditions evaluated changes in physiology and pathophysiology. However, no genome-wide study has been applied to such models. Here we studied the histopathologic changes in testes of rats under different durations of stress and used RNA sequencing (RNA-seq) to investigate the testicular transcriptome and detect differentially expressed genes. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and immunohistochemistry were used to verify these. Chronic stress resulted in significant histopathologic changes in seminiferous tubules and RNA-seq showed that growing numbers of genes were dysregulated with increasing stress exposure. Gene Ontology (GO) analysis showed that many biological processes of cell proliferation-associated terms were highly significantly enriched among downregulated genes, from chronically stressed groups. Proliferating cell nuclear antigen (PCNA) was used as a key marker of cell proliferation. RT-qPCR and immunohistochemistry indicated that PCNA mRNA and protein expression levels were greatly decreased with prolonged stress, thereby contributing to the attenuation of spermatogenic cell proliferation in the rat testis. This could provide a new scientific basis for the study of male reproductive dysfunction caused by stress.

The Long Noncoding RNA Lncenc1 Maintains Naive States of Mouse ESCs by Promoting the Glycolysis Pathway.

The naive embryonic stem cells (nESCs) display unique characteristics compared with the primed counterparts, but the underlying molecular mechanisms remain elusive. Here we investigate the functional roles of Lncenc1, a highly abundant long noncoding RNA in nESCs. Knockdown or knockout of Lncenc1 in mouse nESCs leads to a significantly decreased expression of core pluripotency genes and a significant reduction of colony formation capability. Furthermore, upon the depletion of Lncenc1, the expression of glycolysis-associated genes is significantly reduced, and the glycolytic activity is substantially impaired, as indicated by a more than 50% reduction in levels of glucose consumption, lactate production, and extracellular acidification rate. Mechanistically, Lncenc1 interacts with PTBP1 and HNRNPK, which regulate the transcription of glycolytic genes, thereby maintaining the self-renewal of nESCs. Our results demonstrate the functions of Lncenc1 in linking energy metabolism and naive state of ESCs, which may enhance our understanding of the molecular basis underlying naive pluripotency.

Expression of the µ, κ, and δ-opioid receptors and tyrosine hydroxylase in MN9D cells.

Dopaminergic neurons are suggested to be a critical physiopathology substrate for addiction disorders. It is not well known whether the clonal mesencephalic dopaminergic cell line MN9D cells can be applied to study morphine addiction. Immunofluorescence staining and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect protein and mRNA expression of the µ, κ, and δ-opioid receptors in MN9D cells. Immunofluorescence staining of TH was applied to quantify the number of dopaminergic neurons. The results showed that the µ, κ, and δ-receptors were all expressed in MN9D cells, and the number of TH-positive cells was significantly greater in the MN9D cells than SH-SY5Y cells. The data suggest that MN9D cells can be used as an in vitro models in future studies to explore the mechanisms of morphine addiction related to dopaminergic neurons.