Effects of triphenyltin on glycinergic transmission on rat spinal neurons

Exposure to triphenyltin impairs gut integrity, disturbs gut microbiota, and alters fecal metabolites

Triphenyltin is an environmental contaminant widely used in antifouling paints and can cause toxicity in various organs in living organisms. However, its effects on intestinal function and the microbiome of the gut remain unknown. The objective of this study was to explore the intestinal toxicity of triphenyltin in mice by orally administering 0, 1.875, 3.75, and 7.5 mg/Kg to adult male mice for 8 weeks. Results showed that triphenyltin caused ileum tissue damage, induced oxidative stress, upregulated inflammation-related gene expression and increased serum tumor-necrosis factor α (TNF-α) levels in mice. Triphenyltin impaired ileum barrier function by downregulating Muc2, ZO-1, Occludin and their protein levels at 3.75 and 7.5 mg/Kg. TPT exposure led to partial inflammation and decreased mucin mRNA expression in the colon. Triphenyltin altered intestinal micro-ecological balance and fecal metabolome in mice. In conclusion, triphenyltin alters the mouse gut microbiota and fecal metabolome.

Review on endocrine disrupting toxicity of triphenyltin from the perspective of species evolution: Aquatic, amphibious and mammalian

Triphenyltin (TPT) is widely used as a plastic stabilizer, insecticide and the most common fungicide in antifouling coatings. This paper reviewed the main literature evidences on the morphological and physiological changes of animal endocrine system induced by TPT, with emphasis on the research progress of TPT metabolism, neurological and reproductive regulation in animal endocrine system. Similar to tributyltin (TBT), the main effects of TPT on the potential health risks of 25 species of animals, from aquatic animals to mammals, are not only related to exposure dose and time, but also to age, sex and exposed tissue/cells. Moreover, current studies have shown that TPT can directly damage the endocrine glands, interfere with the regulation of neurohormones on endocrine function, and change hormone synthesis and/or the bioavailability (i.e., in the retinoid X receptor and peroxisome proliferator-activated receptor gamma RXR-PPARγ) in target cells. Importantly, TPT can cause biochemical and morphological changes of gonads and abnormal production of steroids, both of which are related to reproductive dysfunction, for example, the imposex of aquatic animals and the irregular estrous cycle of female mammals or spermatogenic disorders of male animals. Therefore, TPT should indeed be regarded as a major endocrine disruptor, which is essential for understanding the main toxic effects on different tissues and their pathogenic effects on endocrine, metabolism, neurological and reproductive dysfunction.

Intra-axonal Ca2+ mobilization contributes to triphenyltin-induced facilitation in glycinergic transmission of rat spinal neurons

Triphenyltin (TPT) is an organotin compound causing environmental hazard to many wild creatures. Our previous findings show that TPT increases of the frequency of spontaneous glycinergic inhibitory postsynaptic currents (sIPSCs) in rat spinal neurons without changing the amplitude and 1/e decay time. In our study, the effects of 2-aminoethoxydiphenyl borate (2-APB), dantrolene sodium, and thapsigargin on sIPSC frequency were examined to reveal the contribution of intra-axonal Ca²⁺ mobilization by adding TPT. 2-APB considerably attenuated the TPT-induced facilitation of sIPSC frequency while dantrolene almost completely masked the TPT effects, suggesting that the TPT-induced synaptic facilitation results from the activation of both IP₃ and ryanodine receptors on endoplasmic reticulum (ER) membrane, though inositol triphosphate (IP₃) receptor is less sensitive to TPT. Thapsigargin itself significantly increased the sIPSC frequency without affecting the current amplitude and decay time. Successive addition of TPT could not further increase the sIPSC frequency in the presence of thapsigargin, indicating that thapsigargin completely masked the facilitatory action of TPT. Results suggest that TPT activates the IP₃ and ryanodine receptors while TPT inhibits the Ca²⁺-pump of ER membranes, resulting in the elevation of intra-axonal Ca²⁺ levels, leading to the increase of spontaneous glycine release from synaptic vesicles.