Effect of chronic unpredicted mild stress-induced depression on clopidogrel pharmacokinetics in rats

Activation of the Oxytocin System in the Hypothalamic Paraventricular Nucleus Improves Stress-Induced Postpartum Depression-Like Behavior in Rats

BACKGROUND

Oxytocin (OT) is a key molecule that not only acts as a uterine-contracting hormone during delivery but is also a critical maternal hormone that enables the social transmission of maternal behavior. Postpartum depression (PPD) is a series of depression-like symptoms that occur especially in women in the perinatal period and is accompanied by the failure to adapt to motherhood as well as impaired parent-infant bonding. However, the mechanism by which OT regulates PPD is still unclear. This study aimed to investigate the correlation between OT levels in the paraventricular nucleus (PVN) and PPD and to explore the potential mechanism underlying the involvement of the OT system in the regulation of PPD.

METHODS

We induced perinatal chronic stress in pregnant rats to establish a PPD model. OT levels in the cerebrospinal fluid (CSF) and PVN were measured throughout the perinatal period. We administered the chemogenetic virus hM3Dq into the PVN, intraperitoneally injected N-oxyclozapine to activate OT-secreting neurons, and observed the effects of OT treatment on behaviors related to PPD. Finally, we investigated the potential mechanism underlying PPD regulation by the OT system via transmission electron microscopy, immunofluorescence (IF), and quantitative real-time PCR (qRT-PCR).

RESULTS

Compared with those in the normal group, CSF oxytocin levels in the postpartum depression group decreased from late pregnancy to lactation (p < 0.001). Chemogenetic activation-induced endogenous OT release in the PVN not only alleviated PPD-like symptoms in rats but also enhanced the intracellular production of OT. Transmission electron microscopy revealed an increase in the size of the Golgi apparatus, endoplasmic reticulum, and dense vesicles within OT neurons. IF and qRT-PCR revealed elevated OT levels and increased oxytocin expression within the PVN following chemogenetic activation (p < 0.01).

CONCLUSION

Lower OT levels are strongly associated with the occurrence of PPD. The release of activated OT has been shown to improve PPD-like behaviors in rats and promote intracellular OT synthesis.

Unveiling the Hub Genes Involved in Cadmium-Induced Hepatotoxicity

Cadmium (Cd) is a highly toxic heavy metal that can cause severe liver damage in both humans and animals. However, the specific genes responsible for Cd-induced hepatotoxicity are still not fully understood. Therefore, the aim of this study was to identify the key genes associated with Cd-induced liver damage. To achieve this, we utilized the GSE19662 dataset from the Gene Expression Omnibus (GEO), which consisted of rat hepatocyte samples treated with cadmium chloride (CdCl2) as well as control groups. By focusing on rat hepatocytes treated with 0.10 ppm of CdCl2, the study identified 851 differentially expressed genes (DEGs), with 438 genes being upregulated and 413 genes being downregulated. Gene Ontology (GO) analysis revealed that these DEGs were primarily involved in inflammatory responses, xenobiotic metabolic processes, and the response to drugs and xenobiotic stimuli. Finally, the study identified several hub genes, including CYP2E1, CYP3A62, CYP2C11, CYP2C13, CYP2B3, HSP90B1, HSP90AA1, GSTA2, and MAPK8, which were associated with CdCl2-induced liver damage. Furthermore, pathway analysis demonstrated that these hub genes were mainly linked to pathways involved in chemical carcinogenesis, metabolic processes, steroid hormone biosynthesis, retinol metabolism, linoleic acid metabolism, arachidonic acid metabolism, inflammatory mediator regulation, Ras, and protein processing in the endoplasmic reticulum. In conclusion, this study provides important insights into the molecular mechanisms underlying Cd-induced liver damage.

Cordyceps cicadae Extracts Exert Antiaging Effects by Activating the AMPK/SIRT1 Pathway in d-Galactose-Induced Aging Rats

Cordyceps cicadae, a valuable traditional edible and medicinal resource, is recognized for its potential in slowing aging but has not been effectively exploited. This study aimed to explore antiaging activity and mechanisms of C. cicadae extracts (CCe). We used liquid chromatography-mass spectrometry to identify 23 CCe compounds and focused on quantifying six nucleoside components as quality markers. We also assessed the antiaging influences in d-galactose (d-gal)-induced aging rats. CCe improved learning memory deficits, enhanced organ indices, and mitigated oxidative brain damage caused by d-gal. CCe elevated superoxide dismutase and glutathione peroxidase activities, while downregulating malondialdehyde. Molecular analyses indicated the involvement of adenosine 5'-monophosphate-activated protein kinase/sirtuin 1 (AMPK/SIRT1) pathway in the antiaging mechanism of CCe. This study demonstrates the potential of CCe in mitigating d-gal-induced damage in aging rats, with the AMPK/SIRT1 pathway emerging as a regulatory axis. These findings contribute to the theoretical foundation for developing antiaging pharmaceuticals and functional foods using CCe, offering promising applications in aging-related contexts in succinct manner.

Plasma exosomal miR-30a-5p inhibits osteogenic differentiation of bone marrow mesenchymal stem cells from a chronic unpredictable mild stress-induced depression rat model

With rising society stress, depression-induced osteoporosis is increasing. However, the mechanism involved is unclear. In this study, we explored the effect of plasma exosomal miRNAs on bone marrow mesenchymal stem cell (BMSC) osteogenic differentiation in a chronic unpredictable mild stress (CUMS)-induced depression rat model. After 12 weeks of CUMS-induced depression, the pathological changes in the bone tissue and markers of osteogenic differentiation were tested by micro-computed tomography, hematoxylin-eosin staining, and quantitative real-time reverse transcription PCR (qRT-PCR). Plasma exosomes from rats were isolated and co-incubated with BMSCs for 14 d to detect the effect on osteogenic markers. Next-generation sequencing identified the miRNAs in the plasma exosomes, and the differential miRNAs were analyzed and verified by qRT-PCR. BMSCs were infected with lentivirus to upregulate miRNA-30a-5p and incubated in a medium that induced osteogenic differentiation for 14 d. The effect of miR-30a-5p on osteogenic differentiation was determined by qPCR and alizarin red staining. CUMS-induced depression rat model was established successfully, and exhibited reduced bone mass and damaged bone microstructure compared to that of the controls. The observed pathological changes suggested the occurrence of osteoporosis in the CUMS group, and the mRNA expression of osteogenic markers was also significantly reduced. Incubation of BMSCs with plasma exosomes from the CUMS group for 14 d resulted in a significant decrease in the expression of osteogenic markers. Twenty-five differentially expressed miRNAs in plasma exosomes were identified and upregulation of miR-30a-5p was observed to significantly inhibit the expression of osteogenic markers in BMSCs. Our findings contributed to a comprehensive understanding of the mechanism of osteoporosis caused by depression, and demonstrated the potential of miR-30a-5p as a novel biomarker or therapeutic target for the treatment of osteoporosis.

Maternal immune activation induces sex-dependent behavioral differences in a rat model of schizophrenia

Background

Maternal immune activation (MIA) is a mature means to construct a schizophrenia model. However, some preclinical studies have reported that a MIA-induced schizophrenia model seemed to have gender heterogeneity in behavioral phenotype. On the other hand, the MIA's paradigms were diverse in different studies, and many details could affect the effect of MIA. To some extent, it is not credible and scientific to directly compare the gender differences of different MIA programs. Therefore, it is necessary to study whether the sex of the exposed offspring leads to behavioral differences on the premise of maintaining a consistent MIA mode.

Methods

An animal model of schizophrenia was established by the administration of 10 mg/kg Poly (I: C) when dams were on day 9 of gestation. Then, a number of female and male offspring completed a series of behavioral tests during postnatal days 61-75.

Results

Compared with the female control group (n = 14), female MIA offspring (n = 12) showed a longer movement distance (d = 1.07, p < 0.05) and higher average speed (d = 1.08, p < 0.05) in the open field test (OFT). In the Y maze test, the percentage of entering the novel arm of female MIA offspring was lower (d = 0.92, p < 0.05). Compared with the male control group (n = 14), male MIA offspring (n = 13) displayed less movement distance (d = 0.93, p < 0.05) and a lower average speed (d = 0.94, p < 0.05) in the OFT. In the Y maze test, the proportion of exploration time in the novel arm of male MIA offspring was lower (d = 0.96, p < 0.05). In the EPM, male MIA offspring showed less time (d = 0.85, p < 0.05) and a lower percentage of time spent in the open arms (d = 0.85, p < 0.05). Male MIA offspring also had a lower PPI index (76 dB + 120 dB, d = 0.81, p < 0.05; 80 dB + 120 dB, d = 1.45, p < 0.01).

Conclusions

Our results showed that the behavioral phenotypes induced by prenatal immune activation were highly dependent on the sex of the offspring.

Chemogenetic Activation of Oxytocin Neurons Improves Pain in a Reserpine-induced Fibromyalgia Rat Model

Fibromyalgia (FM) is a syndrome characterized by chronic pain with depression as a frequent comorbidity. However, efficient management of the pain and depressive symptoms of FM is lacking. Given that endogenous oxytocin (OXT) contributes to the regulation of pain and depressive disorders, herein, we investigated the role of OXT in an experimental reserpine-induced FM model. In FM model, OXT-monomeric red fluorescent protein 1 (OXT-mRFP1) transgenic rats exhibited increased depressive behavior and sensitivity in a mechanical nociceptive test, suggesting reduced pain tolerance. Additionally, the development of the FM-like phenotype in OXT-mRFP1 FM model rats was accompanied by a significant reduction in OXT mRNA expression in the magnocellular neurons of the paraventricular nucleus. OXT-mRFP1 FM model rats also had significantly fewer tryptophan hydroxylase (TPH)- and tyrosine hydroxylase (TH)-immunoreactive (ir) neurons as well as reduced serotonin and norepinephrine levels in the dorsal raphe and locus coeruleus. To investigate the effects of stimulating the endogenous OXT pathway, rats expressing OXT-human muscarinic acetylcholine receptor (hM3Dq)-mCherry designer receptors exclusively activated by designer drugs (DREADDs) were also assessed in the FM model. Treatment of these rats with clozapine-N-oxide (CNO), an hM3Dq-activating drug, significantly improved characteristic FM model-induced pathophysiological pain, but did not alter depressive-like behavior. The chemogenetically induced effects were reversed by pre-treatment with an OXT receptor antagonist, confirming the specificity of action via the OXT pathway. These results indicate that endogenous OXT may have analgesic effects in FM, and could be a potential target for effective pain management strategies for this disorder.