Combined transcriptome and microbiome analysis reveals the thyrotoxic effects of PM2.5 in female rats.

Pervasive environmental pollutants, specifically particulate matter (PM2.5), possess the potential to disrupt homeostasis of female thyroid hormone (TH). However, the precise mechanism underlying this effect remains unclear. In this study, we established a model of PM2.5-induced thyroid damage in female rats through intratracheal instillation and employed histopathological and molecular biological methods to observe the toxic effects of PM2.5 on the thyroid gland. Transcriptome gene analysis and 16S rRNA sequencing were utilized to investigate the impact of PM2.5 exposure on the female rat thyroid gland. Furthermore, based on the PM2.5-induced toxic model in female rats, we evaluated its effects on intestinal microbiota, TH levels, and indicators of thyroid function. The findings revealed that PM2.5 exposure induced histopathological damage to thyroid tissue by disrupting thyroid hormone levels (total T3 [TT3], (P < 0.05); total T4 [TT4], (P < 0.05); and thyrotropin hormone [TSH], (P < 0.05)) and functional indices (urine iodine [UI], P > 0.05), thus further inducing histopathological injuries. Transcriptome analysis identified differentially expressed genes (DEGs), primarily concentrated in interleukin 17 (IL-17), forkhead box O (FOXO), and other signaling pathways. Furthermore, exposure to PM2.5 altered the composition and abundance of intestinal microbes. Transcriptome and microbiome analyses demonstrated a correlation between the DEGs within these pathways and the flora present in the intestines. Moreover, 16 S rRNA gene sequencing analysis or DEGs combined with thyroid function analysis revealed that exposure to PM2.5 significantly induced thyroid hormone imbalance. We further identified key DEGs involved in thyroid function-relevant pathways, which were validated using molecular biology methods for clinical applications. In conclusion, the homeostasis of the "gut-thyroid" axis may serve as the underlying mechanism for PM2.5-induced thyrotoxicity in female rats.

Curcumin alleviates traumatic brain injury induced by gas explosion through modulating gut microbiota and suppressing the LPS/TLR4/MyD88/NF-κB pathway.

Gas explosions (GE) are a prevalent and widespread cause of traumatic brain injury (TBI) in coal miners. However, the impact and mechanism of curcumin on GE-induced TBI in rats remain unclear. In this study, we simulated GE-induced TBI in rats and administered curcumin orally at a dose of 100 mg/kg every other day for 7 days to modulate the gut microbiota in TBI rats. We employed 16S rRNA sequencing and LC-MS/MS metabolomic analysis to investigate changes in the intestinal flora and its metabolic profile. Additionally, we utilized ELISA, protein assays, and immunohistochemistry to assess neuroinflammatory signaling molecules for validation. In a rat TBI model, GE resulted in weight loss, pathological abnormalities, and cortical hemorrhage. Treatment with curcumin significantly mitigated histological abnormalities and microscopic mitochondrial structural changes in brain tissue. Furthermore, curcumin treatment markedly ameliorated GE-induced brain dysfunction by reducing the levels of several neuroinflammatory signaling molecules, including neuron-specific enolase, interleukin (IL)-1ß, IL-6, and cryptothermic protein 3. Notably, curcumin reshaped the gut microbiome by enhancing evenness, richness, and composition. Prevotella_9, Alloprevotella, Bacilli, Lactobacillales, Proteobacteria, and Gammaproteobacteria were identified as prominent members of the gut microbiota, increasing the linear discriminant analysis scores and specifically enhancing the abundance of bacteria involved in the nuclear factor (NF)-κB signaling pathway, such as Lachnospiraceae and Roseburia. Additionally, there were substantial alterations in serum metabolites associated with metabolic NF-κB signaling pathways in the model group. Curcumin administration reduced serum lipopolysaccharide levels and downregulated downstream Toll-like receptor (TLR)4/myeloid differentiation primary response 88 (MyD88)/NF-κB signaling. Furthermore, curcumin alleviated GE-induced TBI in rats by modulating the gut microbiota and its metabolites. Based on these protective effects, curcumin may exert its influence on the gut microbiota and the TLR4/MyD88/NF-κB signaling pathways to ameliorate GE-induced TBI.