Tributyltin reduces bone mineral density by reprograming bone marrow mesenchymal stem cells in rat.

Tributyltin (TBT), a proven endocrine disrupter, was widely used in industry and agriculture. Previous research showed that TBT could alter the balance between osteogenesis and adipogenesis, which may have significant consequences for bone health. Herein, we exposed male rats to TBT chloride (TBTCl) to evaluate the deleterious effects of TBT on bone. Exposure to 50 µg kg-1 TBT resulted in a significant decrease in bone mineral density (BMD) at the femur diaphysis region in the rat. A dose-dependent increase in lipid accumulation and adipocyte number was observed in the bone marrow (BM) of the femur. Meanwhile, TBTCl treatment significantly enhanced the expression of PPARγ and attenuated the expression of Runx2 and ß-catenin in BM. In addition, serum ALP activity of TBT-exposed rats also showed a dose-dependent decrease. These results suggest that TBT could reduce BMD via inhibition of the Wnt/ß-catenin pathway and skew the adipo-osteogenic balance in the BM of rats.

Tributyltin reduces the levels of serum adiponectin and activity of AKT and induces metabolic syndrome in male mice.

Tributyltin (TBT), a proven environmental obesogen, functions as a nanomolar agonist of the peroxisome proliferator activated receptor-γ (PPARγ). However, the adverse effects of TBT on metabolism are incompletely understood. In this study, male ICR mice were administered TBT (5 and 50 µg·kg-1 ) by an intraperitoneal injection once every 3 days for 30 days from 28 days of age and bred for another 30 days after the last administration of TBT. We analyzed the effects of these exposures on the fat depot weights, serum lipid profile, serum leptin and adiponectin, hepatic lipid accumulation, and activity of AKT in the liver and skeletal muscle isolated from mice 8 mins after receiving an insulin injection. Pubertal exposure to TBTCl resulted in a higher body weight, increased epididymal and liver fat accumulation, hyperlipidemia, an elevated low-density lipoprotein/high-density lipoprotein ratio, serum adiponectin deficiency, worse glucose tolerance, and lower insulin-dependent AKT phosphorylation in the liver and muscle in mice. These results showed that TBT exposure induced peripheral insulin resistance and metabolic syndrome in mice.

Acrylamide Retards the Slow Axonal Transport of Neurofilaments in Rat Cultured Dorsal Root Ganglia Neurons and the Corresponding Mechanisms.

Chronic acrylamide (ACR) exposure induces peripheral-central axonopathy in occupational workers and laboratory animals, but the underlying mechanisms remain unclear. In this study, we first investigated the effects of ACR on slow axonal transport of neurofilaments in cultured rat dorsal root ganglia (DRG) neurons through live-cell imaging approach. Then for the underlying mechanisms exploration, the protein level of neurofilament subunits, motor proteins kinesin and dynein, and dynamitin subunit of dynactin in DRG neurons were assessed by western blotting and the concentrations of ATP was detected using ATP Assay Kit. The results showed that ACR treatment results in a dose-dependent decrease of slow axonal transport of neurofilaments. Furthermore, ACR intoxication significantly increases the protein levels of the three neurofilament subunits (NF-L, NF-M, NF-H), kinesin, dynein, and dynamitin subunit of dynactin in DRG neurons. In addition, ATP level decreased significantly in ACR-treated DRG neurons. Our findings indicate that ACR exposure retards slow axonal transport of NF-M, and suggest that the increase of neurofilament cargoes, motor proteins, dynamitin of dynactin, and the inadequate ATP supply contribute to the ACR-induced retardation of slow axonal transport.

Peripubertal exposure to low doses of tributyltin chloride affects the homeostasis of serum T, E2, LH, and body weight of male mice.

Previous studies have shown that tributyltin could act as an endocrine disruptor in mammals. However, the data on the low-dose effect of tributyltin in animals are still lacking. The objective of this study was to demonstrate the endocrine disruption induced by low levels of tributyltin chloride (TBTCl) in male KM mice. The animals were treated with 0.05 or 0.5 mg TBTCl/kg body weight/3 days from postnatal days (PNDs) 24 to 45, and killed on PNDs 49 and 84, respectively. Mice treated with 0.5 mg TBTCl/kg exhibited decreased serum and intratesticular testosterone (T) levels on PND 49 and then followed by an obvious recovery on PND 84. Furthermore, mice treated with 0.05 mg TBTCl/kg showed reduced serum 17ß-estradiol (E2) levels on PND 49. However, treatments with TBTCl resulted in a dose-dependent increase in serum E2 concentration of the mice on PND 84. Administration of TBTCl also decreased levels of serum luteinizing hormone and intratesticular E2 on PND 84. In addition, mice exposed to 0.05 mg/kg TBTCl exhibited an increase in body weight in the late stage of the experiment. These results indicate that treatment with low doses of TBTCl could disturb hormone homeostasis and body weight gain in rodents, and exposure to different levels of TBTCl might have different effects on changing some physiologic parameters.