Animal models in intrauterine adhesion research

SCGB1D4 downregulation links to fibrosis in intrauterine adhesion patients and rat models†

Intrauterine adhesions (IUA) represent a prevalent uterine endometrial disorder frequently correlated with menstrual irregularities and infertility. Some members of the secretoglobin(SCGB) family have demonstrated anti-fibrotic effects, however, the specific role of SCGB1D4, one of the family members, in anti-fibrosis remains unclear. This study aimed to investigate the expression of SCGB1D4 in IUA tissues, validate the role of SCGB1D4 in endometrial fibrosis, and assess its potential therapeutic significance by analyzing clinical features and constructing rat and cell models. Clinical characteristics of patients with intrauterine adhesions (IUA) were compared and analyzed against control subjects. Additionally, a rat uterine adhesion model was successfully established using a combination of mechanical injury and infection. The expression levels of SCGB1D4 in patient tissues and animal models were detected through immunohistochemistry, Western blot, and real-time fluorescence quantitative PCR, and the changes in fibrosis markers COL1A1 and α-SMA were also evaluated. Furthermore, human endometrial stromal cell lines (HESCs) induced by transforming growth factor-β-1 conversion were differentiated into myofibroblasts to establish cell models of intrauterine adhesion. We detected the expression of SCGB1D4 and fibrosis-related factors by real-time fluorescence quantitative PCR and Western blot. Cell proliferation and cell cycle changes were assessed using flow cytometry and CCK8. IUA patients showed increased miscarriage rates and decreased endometrial thickness. Clinical tissue specimens revealed significantly lower expression of SCGB1D4 in the endometrial tissues of IUA patients, accompanied by a notable increase in COL1A1 and α-SMA. The established rat model of intrauterine adhesion exhibited decreased expression of SCGB1D4 and a significant increase in fibrosis. After overexpression of SCGB1D4 on the IUA cell model, SCGB1D4 expression was elevated, while COL1A1 and α-SMA expression was significantly reduced. Cell proliferation was inhibited and cell cycle distribution was altered. This study has confirmed the low expression of SCGB1D4 in patients with IUA, as well as in animal and cell models. Furthermore, the overexpression of SCGB1D4 in a cell model of IUA demonstrates that it may play a key role in inhibiting fibrosis. SCGB1D4 holds promise as a potential therapeutic target for IUA, providing a new avenue for overcoming fertility issues caused by IUA.

Ziziphus jujube promotes fertility and pregnancy outcomes in Rat model of uterine adhesions

Introduction

The therapeutic efficacy of oral administration of Ziziphus jujube in the context of uterine adhesion (UA) and its impact on pregnancy outcomes was investigated.

Methods

In a rat UA model, Z. jujube was evaluated for its ability to mitigate injury-induced uterine adhesion bands, uterine shortening, and enhance endometrial regeneration. The assessment included analysis of gland numbers, uterine endometrial thickness, and regulation of inflammatory cytokines. The antioxidant properties of Z. jujube were also studied through antioxidant enzyme activity in uterine tissue homogenates. Fibrotic changes were examined through histological Trichrome staining and analysis of pro-fibrotic factors.

Results

Treatment with Z. jujube resulted in a significant reduction in uterine tissue fibrosis, as evidenced by histological evaluation and reduced expression of fibrotic markers. The intervention demonstrated positive outcomes in embryonic development, pregnancy rates, and pregnancy outcomes. Z. jujube effectively inhibited the formation of extra-uterine adhesion bands to internal organs. No toxicity-related morphological changes were observed in vital organs of the Z. Jujube-treated group.

Discussion

The results collectively indicate that Z. jujube is a safe and potent natural product with anti-inflammatory and anti-fibrotic properties, highlighting its potential as a novel candidate for clinical studies targeting UA in patients.

Strategies and Challenges of Mesenchymal Stem Cells-Derived Extracellular Vesicles in Infertility

Having genetically related offspring remains an unattainable dream for couples with reproductive failure. Mesenchymal stem cells (MSCs) are multipotent stromal cells derived from various human tissues and organs. As critical paracrine effectors of MSCs, extracellular vesicles (EVs) can carry and deliver bioactive content, thereby participating in intercellular communication and determining cell fate. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have shown promising therapeutic effects, including repairing injured endometria, restoration of ovarian functions, and improving sperm quantity, morphology, and motility, owing to their regenerative potential, abundant sources, high proliferation rates, low immunogenicity, and lack of ethical issues. However, limited knowledge on purification and isolation of MSC-EVs, therapeutic effects, and unpredictable safety have caused challenges in overcoming female and male infertility. To overcome them, future studies should focus on modification/engineering of MSC-EVs with therapeutic biomolecules and combining attractive biomaterials and MSC-EVs. This review highlights the latest studies on MSC-EVs therapies in infertility and the major challenges that must be overcome before clinical translation.

The disordered extracellular matrix landscape induced endometrial fibrosis of sheep: A multi-omics integrative analysis

Endometrial fibrosis leads to the destruction of endometrial function and affects reproductive performance. However, mechanisms underlying the development of endometrial fibrosis in sheep remain unclear. We use transcriptomic, proteomic, and metabolomic studies to reveal the formation mechanisms of endometrial fibrosis. The results showed that the fibrotic endometrial tissue phenotype presented fewer glands, accompanied by collagen deposition. Transcriptomic results indicated alterations in genes associated with the synthesis and degradation of extracellular matrix components, which alter metabolite homeostasis, especially in glycerophospholipid metabolism. Moreover, differentially expressed metabolites may play regulatory roles in key metabolic processes during fibrogenesis, including protein digestion and absorption, and amino acid synthesis. Affected by the aberrant genes, protein levels related to the extracellular matrix components were altered. In addition, based on Kyoto Encyclopedia of Genes and Genomes analysis of differentially expressed genes, metabolites and proteins, amino acid biosynthesis, glutathione, glycerophospholipid, arginine and proline metabolism, and cell adhesion are closely associated with fibrogenesis. Finally, we analyzed the dynamic changes in serum differential metabolites at different time points during fibrosis. Taken together, fibrosis development is related to metabolic obstacles in extracellular matrix synthesis and degradation triggered by disturbed gene and protein levels.

Mechanisms of Regeneration and Fibrosis in the Endometrium

The uterine lining (endometrium) regenerates repeatedly over the life span as part of its normal physiology. Substantial portions of the endometrium are shed during childbirth (parturition) and, in some species, menstruation, but the tissue is rapidly rebuilt without scarring, rendering it a powerful model of regeneration in mammals. Nonetheless, following some assaults, including medical procedures and infections, the endometrium fails to regenerate and instead forms scars that may interfere with normal endometrial function and contribute to infertility. Thus, the endometrium provides an exceptional platform to answer a central question of regenerative medicine: Why do some systems regenerate while others scar? Here, we review our current understanding of diverse endometrial disruption events in humans, nonhuman primates, and rodents, and the associated mechanisms of regenerative success and failure. Elucidating the determinants of these disparate repair processes promises insights into fundamental mechanisms of mammalian regeneration with substantial implications for reproductive health.