Melatonin or vitamin C attenuates lead acetate-induced testicular oxidative and inflammatory damage in mice by inhibiting oxidative stress mediated NF-κB signaling.

Lead (Pb) acts as an environmental endocrine disruptor and has negative effects in animals; excessive accumulation of lead causes reproductive dysfunction in male animals. Oxidative stress plays a vital role in Pb-induced injury. However, the mechanisms underlying chronic testicular toxicity of Pb remain unclear. In this study, we aimed to determine the effects of lead acetate on reproductive function in male mice, identify the underlying mechanisms, and test counter measures to alleviate the toxic effects. Male mice were dosed with lead acetate (500 mg/L) in free drinking water for 12 weeks, and administered melatonin (5 mg/kg) or vitamin C (500 mg/kg) by intraperitoneal injection. Blood from the eyeball, testicles, and sperm from the caudal epididymis were collected after 12 weeks and analyzed. Pb exposure reduced sperm count and motility, increased sperm malformation (P < 0.01), disrupted testicular morphology and structure, and decreased the expression of steroid hormone synthesis-related enzymes and serum testosterone concentration (P < 0.01). Pb also increased the number of inflammatory cells and the levels of the pro-inflammatory cytokines TNF-α and IL-6 (P < 0.01), and activated NF-κB signaling. Furthermore, the ROS yield and oxidation indicators LPO and MDA were significantly increased (P < 0.01), and the antioxidant indicators T-AOC, SOD, and GSH were significantly reduced (P < 0.01). Treatment with melatonin or vitamin C reversed the effects of lead acetate; vitamin C was more effective in restoring SOD activity (P < 0.01) and enhancing ZO-1 protein levels (P < 0.01). Thus, long-term exposure to lead acetate at low concentrations could adversely affect sperm quality and induce inflammatory damage by oxidative stress mediated NF-κB signaling. Vitamin C could act as a protective agent and improve reproductive dysfunction in male animals after lead accumulation.

Single-cell transcriptomic, transcriptomic, and metabolomic characterization of human atherosclerosis.

Background: Atherosclerosis is the main cause of many cardiovascular and cerebrovascular diseases (CVDs), and gaining a deeper understanding of the intercellular connections and key central genes which mediate formation of atherosclerotic plaques is required. Methods: We performed a comprehensive bioinformatics analysis of differential genetic screening, Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway annotation, protein-protein interactions (PPIs), pseudo-timing, intercellular communication, transcription factors on carotid single-cell sequencing data, and aortic bulk transcriptome and metabolomic data. Results: Ten cell types were identified in the data: T cells, monocytes, smooth muscle cells, endothelial cells, B cells, fibroblasts, plasma cells, mast cells, dendritic cells, and natural killer cells. Endothelial, fibroblast, macrophage, and smooth muscle cell subtype differentiation trajectories, interaction networks, and important transcription factors were characterized in detail. Finally, using this information combined with transcriptome and metabolome analyses, we found the key genes and signaling pathways of atherosclerosis, especially the advanced glycation end products and receptor for advanced glycation end products signaling pathway (AGE-RAGE signaling pathway) in diabetic complications, linked the differential metabolites with fibroblasts and atherosclerosis and contributed to it in patients with diabetes. Conclusions: Collectively, this study provides key genes, signaling pathways, cellular communication, and transcription factors among endothelial cells, fibroblasts, macrophages, and smooth muscle cells for the study of atherosclerotic plaques, and provides a basis for the diagnosis and treatment of atherosclerosis-like sclerosis.

[A new method of microglia sorting and functional characteristics of spinal microglia in aged rats].

Objective: To establish an improved method of separating microglia from aged rats and to observe the biological characteristics of spinal microglia of aged rats. Methods: Young SD rats (2 months) were used as control group. Single cell suspension of rat microglia were prepared by trypsin, trypsin substitutes or mechanical net rubbing method. Then, by assessing the purity and survival rate of cells, and observing the morphological characteristics and analyzing the inflammatory functional characteristics, we optimized the isolation and purification method of microglia from aged rats (20 months old) , and observed the functional characteristics of spinal microglia in aged rats. Results: The survival rate of cells digested by pancreatic enzyme was low(young rats 83%, aged rats 60%). Although the survival rate of mechanical net rubbing method was higher than that of pancreatic enzyme digest methods (95%), the cell acquisition rate was lower(young rats(0.207±0.020)×106, aged rats(0.243±0.023)×106). Trypsin substitute dissociation combining density gradient centrifugation method was the best way to get abundant, active and higher survival microglia, and the purity reached more than 85%. We used this method to separate microglia from spinal cord of rats. Compared with the young rats, the spinal cord tissue of old rats was larger, the digestive fluid volume was higher, but the digestion time was shorter. Compared with the young rats, the aged rat spinal microglia had larger and rounder cell body, fewer and shorter protrusions, it tended to be activated morphologically, the level of proinflammatory cytokine IL-1ß of microglia in aged rats was lower, and the level of antiinflammatory factor IL-10 was higher. Conclusion: The method of trypsin substitute dissociation combined with density gradient centrifugation was successfully established to isolate and purify microglia from spinal cord of rats, the spinal microglia of old rats showed anti-inflammatory phenotype.

SLC40A1 Mediates Ferroptosis and Cognitive Dysfunction in Type 1 Diabetes.

Cognitive dysfunction often accompanies diabetes. Both hypoglycemia and hyperglycemia cause cognitive dysfunctions. However, the underlying pathophysiology remains unclear. Recent evidence show that ferroptosis primarily triggers nerve cell death, Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). The present study aimed to investigate whether ferroptosis is a vital pathogenic pathway in diabetes-induced cognitive dysfunction. Type 1 diabetic rat model was created by intraperitoneal injection of streptozotocin (STZ). Significant cognitive dysfunction was observed in the diabetic rats as evidenced by increase in latency period to find a hidden platform and decreased cumulative time spent in the target quadrant (TQ) in the Morris water maze test. We detected the amplitude of low-frequency fluctuation (ALFF) of the BOLD (Blood Oxygenation Level-Dependent) signal using resting-state functional magnetic resonance imaging (rs-fMRI). Consequently, we found that the ALFF values, as well as the T2 relaxation time of the bilateral hippocampus, were reduced in Type 1 diabetic rats. We detected Fe2+ level and lipid peroxidation products (malondialdehyde (MDA) and 4-Hydroxynonenal (4-HNE)) in the hippocampus. Mitochondria and neuron injury in the STZ-induced diabetic rats were determined using a Transmission Electron Microscope and Nissl body staining. Iron overload and ferroptosis were detected in the hippocampus. Furthermore, mRNA microarray analysis revealed 201 dysregulated mRNAs in STZ-induced type 1 diabetes (T1D). Pathway enrichment analyses indicated that differentially expressed mRNAs associated-coding genes were associated with ferroptosis. Among ferroptosis signaling pathway genes, Slc40a1 gene (ferroportin) was downregulated. We show that ferroptosis is associated with diabetic cognitive dysfunction and Slc40a1 mediates ferroptosis in T1D.

Age-related shifts in gut microbiota contribute to cognitive decline in aged rats.

Cognitive function declines during the aging process, meanwhile, gut microbiota of the elderly changed significantly. Although previous studies have reported the effect of gut microbiota on learning and memory, all the reports were based on various artificial interventions to change the gut microbiota without involvement of aging biological characteristics. Here, we investigated the effect of aged gut microbiota on cognitive function by using fecal microbiota transplantation (FMT) from aged to young rats. Results showed that FMT impaired cognitive behavior in young recipient rats; decreased the regional homogeneity in medial prefrontal cortex and hippocampus; changed synaptic structures and decreased dendritic spines; reduced expression of brain-derived neurotrophic factor (BDNF), N-methyl-D-aspartate receptor NR1 subunit, and synaptophysin; increased expression of advanced glycation end products (AGEs) and receptor for AGEs (RAGE). All these behavioral, brain structural and functional alterations induced by FMT reflected cognitive decline. In addition, FMT increased levels of pro-inflammatory cytokines and oxidative stress in young rats, indicating that inflammation and oxidative stress may underlie gut-related cognitive decline in aging. This study provides direct evidence for the contribution of gut microbiota to the cognitive decline during normal aging and suggests that restoring microbiota homeostasis in the elderly may improve cognitive function.