Constant light exposure alters gut microbiota and short-/medium-chain fatty acids and aggravates PCOS-like traits in HFD-fed rats

Ascorbic acid Mitigates behavioural disturbances associated with letrozole-induced PCOS via switching-off JAK2/STAT5 and JAK2/ERK1/2 pathways in rat hippocampus

PURPOSE

Polycystic ovary syndrome (PCOS) is an endocrine disorder with the highest prevalence among other disorders in sexually-active women. It is associated with broad-spectrum hormonal and metabolic disturbances with behavioural difficulties. Experimentally, letrozole administration causes similar findings. Ascorbic acid is powerful anti-oxidant; and its cellular levels decrease with "hyperglycemic and poor anti-oxidative" status, which is, a main hallmark of PCOS. Thus, ascorbic acid administration may prevent the induction of PCOS and its consequences.

BASIC PROCEDURES

Forty female rats were divided into four groups (n = 10 in each): normal control (CTRL), ascorbic acid (ASC), letrozole (LTZ), and ascorbic acid + letrozole (ASC + LTZ) group. Behavioural tests (Y-maze spontaneous alteration, tail suspension test, forced swimming test) were performed. In serum, hormones (testosterone, estradiol, progesterone), glycemia (blood glucose, insulin and HOMA-IR) and oxidative stress (SOD activity, GSH) markers were measured. In hippocampus, inflammation and apoptosis indicators (p-JAK2, p-STAT5, p-ERK1/2, NF-κB, BAX, Bcl2, BAX/Bcl2 ratio) and neurotransmitters (DA, 5-HT, NE, BDNF) were determined. Lastly, ovary histopathological investigation was conducted to confirm PCOS induction.

PRINCIPAL RESULTS

Letrozole induced PCOS with subsequent disturbances. Testosterone levels were augmented while estradiol and progesterone were declined. Fasting blood glucose, insulin, HOMA-IR and oxidative stress markers were elevated. The expression of p-JAK2, p-STAT5, p-ERK1/2, BAX and the levels of NF-κB were increased, but Bcl2 expression, monoamines and BDNF levels were lowered. Importantly, ASC restored the last mentioned parameters markedly.

MAJOR CONCLUSIONS

Ascorbic acid mitigated the behavioural difficulties of PCOS possibly by switching-off JAK2/STAT5 and JAK2/ERK1/2 pathways in hippocampus along with its neurotransmission-improving, hormonal-normalizing, anti-hyperglycemic and anti-oxidative effects.

Multiple effects of kisspeptin on neuroendocrine, reproduction, and metabolism in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a highly prevalent and heterogeneous disease characterized by a combination of reproductive and endocrine abnormalities, often associated with metabolic and mental health disorders. The etiology and pathogenesis of PCOS remain unclear, but recent research has increasingly focused on the upstream mechanisms underlying its development. Among these, kisspeptin (KISS) signaling has emerged as a pivotal component in the regulation of the hypothalamic-pituitary-gonadal axis, with significant roles in reproductive function, energy regulation, and metabolism. Women with PCOS commonly exhibit disruptions in gonadotropin secretion, including elevated luteinizing hormone (LH) levels, imbalanced LH/follicle-stimulating hormone (FSH) ratios, and increased androgen levels, all of which are usually parallel with abnormal KISS signaling. Furthermore, alterations in the KISS/KISS1R system within the central and circulatory systems, as well as peripheral tissues, have been implicated in the development of PCOS. These changes affect multiple pathophysiological domains, including reproductive function, energy regulation, metabolic homeostasis, inflammatory response, and emotional disorders, and are further influenced by lifestyle and environmental factors. This review aims to comprehensively summarize the existing experimental and clinical evidence supporting these roles of KISS in PCOS, with the goal of establishing a foundation for future research and potential clinical applications.

Gut microbiota and mycobiota change with feeding duration in mice on a high-fat and high-fructose diet

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD), formerly known as nonalcoholic fatty liver disease (NAFLD), is becoming the most common chronic liver disease. The gut microbiome is regarded to play a crucial role in MAFLD, but the specific changes of gut microbiome, especially fungi, in different stages of MAFLD are not well understood. This study aimed to observe the longitudinal changes of colon bacteria and fungi of mice at different feeding duration of a high-fat and high-fructose diet (HFHFD), and explore the association between the changes and the progression of MAFLD.

METHODS

Twenty-eight male C57BL6J mice were randomly assigned to the normal diet (ND) group and HFHFD group. At the 8th and 16th weeks, mice were sacrificed to compare the diversity, composition, and co-abundance network of bacteria and fungi in colon contents among groups.

RESULTS

HFHFD-8W mice exhibited increases in Candida and Dorea, and decreases in Oscillospira and Prevotella in comparison to ND-8W mice, HFHFD-16W mice had increases in Bacteroides, Candida, Desulfovibrio, Dorea, Lactobacillus, and Rhodotorula, and decreases in Akkermansia, Aspergillus, Sterigmatomyces, and Vishniacozyma in comparison to ND-16W mice. And compared to HFHFD-8W mice, HFHFD-16W mice had increases in Desulfovibrio, Lactobacillus, Penicillium, and Rhodotorula, and decreases in Talaromyces and Wallemia. Spearman and GEE correlation analysis revealed that Bacteroides, Candida, Desulfovibrio, and Lactobacillus positively correlated with NAFLD activity score (NAS).

CONCLUSION

Gut microbiota and mycobiota undergo diverse changes at different stages of MAFLD.

CLINICAL TRIAL NUMBER

Not applicable.

Dynamic changes of fatty acids and (R)-dichlorprop toxicity in Arabidopsis thaliana: correlation, mechanism, and implications

Plant fatty acids (FAs) are critical components of lipids and play an important role in coping with pollution-induced stress. However, the relationship between the fluctuating changes of FAs and the toxic effects of pollutants is not clear. Here, we analyzed and identified 19 FAs, namely 14 medium and long chain fatty acids (MLCFAs) and 5 very long chain fatty acids (VLCFAs). First, a positive correlation between plant biomass and LCFA content was observed. Changes in unsaturation were inversely related to cell membrane permeability, which serves as an indicator of the toxic effects. In particular, the use of herbicides led to a reduction in total FA content, but caused a significant increase in free fatty acids (FFAs), which facilitate oxidative stress. In addition, supplementation with exogenous FAs, particularly linoleic and alpha-linolenic acids, effectively alleviated the toxic inhibition. (R)-dichlorprop causes abnormal FA metabolism that can be reversed by ferrostatin-1, a ferroptosis inhibitor. Under (R)-dichlorprop exposure, the balance of FA unsaturation in plants is disrupted by inhibition of FA desaturase activity, ultimately leading to ferroptosis and disruption of cell membrane integrity. This study aims to enhance the understanding of the ecotoxic effects of herbicides by examining changes in FAs. The findings will provide a scientific basis for controlling environmental risks associated with hazardous substances.

Polycystic ovary syndrome: Insights into its prevalence, diagnosis, and management with special reference to gut microbial dysbiosis

Polycystic ovary syndrome (PCOS) represents major endocrine and metabolic disorder among women largely characterized by hyperandrogenism and oligomenorrhea precipitates serious complications such as type 2 diabetes, early atherosclerosis, infertility, and endometrial cancer. Several etiological theories were proposed to define the exact cause of the PCOS, which is characterized, by the hypothalamic-pituitary axis, ovarian morphology, and release of adrenal steroid hormones, metabolic syndrome, and hereditary factors. The review explored the role of dysbiosis and the mechanisms through which microbial dysbiosis can affect PCOS development. In recent time, various research groups highlighted the role of microbial gut dysbiosis associated with obesity as potential etiological factor for the PCOS. In the present review, we reviewed the mechanisms attributed to the microbial dysbiosis and treatment approaches to deal with the situation.

Melatonin-mediated corrective changes in gut microbiota of experimentally chronodisrupted C57BL/6J mice

Chronic consumption of a high-calorie diet coupled with an altered sleep-wake cycle causes disruption of circadian clock that can impact the gut microbiome leading to metabolic syndrome and associated diseases. Herein, we investigate the effects of a high fat high fructose diet (H) alone or in combination with photoperiodic shifts induced chronodisruption (CD) on gut microbiota of C57BL/6J male mice. Further, the merits of daily evening intraperitoneal administration of melatonin in restoring gut microbiota are studied herein. Experimental groups viz. H, CD and HCD mice recorded higher levels of serum pro-inflammatory cytokines (TNF-α and IL-6) and lower levels of the anti-inflammatory cytokine, IL-10. These findings correlate with a concomitant increase in the transcripts of TLR4, TNF-α, and IL-6 in small intestine of the said groups. A decrement in mRNA levels of Ocln, ZO-1 and Vdr in these groups implied towards an altered gut permeability. These results were in agreement with the observed decrement in percentage abundance of total gut microflora and Firmicutes: Bacteroidetes (F/B) ratio. Melatonin administration accounted for lower-level inflammation (serum and gut) along with an improvement in gut permeability markers. The total abundance of gut microflora and F/B ratio showed an improvement in all the melatonin-treated groups and the same is the highlight of this study. Taken together, our study is the first to report perturbations in gut microbiota resulting due to a combination of photoperiodic shifts induced CD and a high fat high calorie diet-induced lifestyle disorder. Further, melatonin-mediated rejuvenation of gut microbiome provides prima facie evidence of its role in improving gut dysbiosis that needs a detailed scrutiny.

Unraveling the complexity of polycystic ovary syndrome with animal models

Polycystic ovary syndrome (PCOS) is a highly familial and heritable endocrine disorder. Over half of the daughters born to women with PCOS may eventually develop their own PCOS-related symptoms. Progress in the treatment of PCOS is currently hindered by the complexity of its clinical manifestations and incomplete knowledge of its etiopathogenesis. Various animal models, including experimentally induced, naturally occurring, and spontaneously arising ones, have been established to emulate a wide range of phenotypical and pathological traits of human PCOS. These studies have led to a paradigm shift in understanding the genetic, developmental, and evolutionary origins of this disorder. Furthermore, emerging evidence suggests that animal models are useful in evaluating state-of-the-art drugs and treatments for PCOS. This review aims to provide a comprehensive summary of recent studies of PCOS in animal models, highlighting the power of these disease models in understanding the biology of PCOS and aiding high-throughput approaches.

Associations of nighttime light exposure during pregnancy with maternal and neonatal gut microbiota: A cohort study

BACKGROUND

Nighttime light (NTL) pollution has been reported as a risk factor for human health. However, the relationship between NTL and gut microbiota has not been reported in pregnant women and neonates. This study was conducted to investigate the relationship between NTL and gut microbial diversity and composition in mothers and their neonates.

METHODS

This study analyzed 44 mothers and 28 newborns. The composition of gut microbiota was evaluated using 16S rRNA V3-V4 sequencing. The monthly mean NTL exposure during pregnancy was respectively calculated based on each participant's residential address (NTLpoint) and a concentric 1 km radius buffer zone around their address (NTL1000m). The relationships between NTL exposure and gut microbiota of mothers and newborns were assessed using generalized linear models.

RESULTS

NTL exposure during pregnancy was not associated with alpha diversity of mothers or neonates. For mothers, results revealed that after adjusting for covariates, NTLpoint was negatively correlated with Prevotella_2 (p = 0.004, FDR-adjusted p = 0.030) and norank_o__Gastranaerophilales (p = 0.018, FDR-adjusted p = 0.049) at the genus level. In addition, Lachnospira (p = 0.036, FDR-adjusted p = 0.052) and Coprococcus_3 (p = 0.025, FDR-adjusted p = 0.052) were positively correlated with NTLpoint. The association between Coprococcus_3 (p = 0.01, FDR-adjusted p = 0.046) and NTLpoint persisted even after controlling for covariates. For neonates, Thauera was positively associated with NTLpoint (p = 0.015) and NTL1000m (p = 0.028), however, after adjusting for covariates and FDR correction, Thauera was not significantly associated with NTLpoint and NTL1000m.

CONCLUSIONS

This study found that NTL exposure was associated with maternal gut microbiota composition. Our findings provide a foundation for the potential impact of NTL exposure on maternal gut microbiota from a microbiological perspective. More population-based validation of the effects of NTL exposure on human gut microbiota is needed in future.

Central blockage of sympathetic nerves inhibits the abnormal vital signs and disturbance of the gut microbiota caused by continuous light exposure

Background

Continuous light exposure increases sympathetic excitation in rats, leading to hypertension, left ventricular hypertrophy, and fibrosis. This study was aimed to investigate whether continuous light exposure causes destabilization of vital signs and gut microbiota (GM) in Sprague Dawley (SD) rats and whether clonidine hydrochloride (CH), a central sympathetic depressant drug, could prevent these changes.

Methods

Eight-week-old male SD rats were divided into three groups with different interventions for 14 weeks: control group (CG), 2-mL pure water gavaged daily while on a normal 12-h light/dark cycle; continuous illumination group (CI), 2-mL pure water gavaged daily while receiving continuous exposure to light (300 lx); and drug administration group (DA), CH (10 μg/kg) gavaged daily while receiving continuous exposure to light (300 lx).

Results

The results showed that blood pressure, heart rate, and body weight were significantly higher in the CI group than in the CG and DA groups (P < 0.05). Moreover, the Shannon index was higher in the DA group than in the CI group (P = 0.012). The beta diversity index in the CG group was significantly higher in the CI group (P = 0.039). The pairwise comparison results of the linear discriminant analysis effect size showed that Oscillospirales were enriched in the DA group, whereas the Prevotellaceae lineage (family level) > Prevotella (genus level) > Prevotellaceae_bacterium (species level) were enriched in the CI group. The Muribaculaceae family was more abundant in the CG group than in the CI group.

Conclusion

Sympathetic nerve inhibition restored the abnormal vital signs and GM changes under continuous light exposure.

[The interactions along the microbiota-gut-brain axis in the regulation of circadian rhythms, sleep mechanisms and disorders]

The bidirectional relationship between cerebral structures and the gastrointestinal tract involving the microbiota embraces the scientific concept of the microbiota-gut-brain axis. The gut microbiome plays an important role in many physiological and biochemical processes of the human body, in the immune response and maintenance of homeostasis, as well as in the regulation of circadian rhythms. There is a relationship between the higher prevalence of a number of neurological disorders, sleep disorders and changes in the intestinal microbiota, which actualizes the study of the complex mechanisms of such correlation for the development of new treatment and prevention strategies. Environmental factors associated with excessive light exposure can aggravate the gut dysbiosis of intestinal microflora, and as a result, lead to sleep disturbances. This review examines the integrative mechanisms of sleep regulation associated with the gut microbiota (the role of neurotransmitters, short-chain fatty acids, unconjugated bile acids, bacterial cell wall components, cytokines). Taking into account the influence of gut dysbiosis as a risk factor in the development of various diseases, the authors systematize key aspects and modern scientific data on the importance of microflora balance to ensure optimal interaction along the microbiota-gut-brain axis in the context of the regulatory role of the sleep-wake cycle and its disorders.

Association between mobile phone addiction, sleep disorder and the gut microbiota: a short-term prospective observational study

Bidirectional communication between the gut microbiota and the brain has sparked interest in exploring the link between mobile phone addiction (MPA) and sleep disorders (SD) in microbiome research. However, investigating the role of gut microbiota in this relationship using animal models presents challenges due to the unique nature of MPA, and human research in this area is scarce. We recruited 99 healthy college students to evaluate the gut microbiome using 16S rRNA gene amplicon sequencing and assess MPA and SD at baseline and after a two-month follow-up. Multiple covariate-adjusted statistical models, including linear regression, permutational multivariate analysis of variance and so on, were employed to determine microbiome associations with MPA at baseline and changes in SD at follow-up. Our findings revealed negative associations between MPA and three alpha diversity metrics, along with alterations in bacterial composition. MPA showed negative associations with the relative abundance of Bacteroidetes, while displaying positive associations with Actinobacteria and Bifidobacteriales. Conversely, Actinobacteria exhibited a negative association with increased SD. This study has established a significant link between MPA and a decrease in the alpha diversity of the gut microbiota. Actinobacteria was associated with MPA and SD, respectively. Additional investigation is needed to fully comprehend the relationship between comorbid behavioral disorders and the gut microbiota.