Taurine attenuates acrylamide-induced axonal and myelinated damage through the Akt/GSK3β-dependent pathway

The protective effect of rutin on sciatic nerve injury in acrylamide-exposed rats and its mechanisms

Rutin (Rut) is a flavonoid with pharmacological activities such as anti-inflammatory and antioxidant. Acrylamide (ACR) is a toxic substance widely found in human life that can induce neurotoxicity. Some studies have confirmed that neurotoxicity caused by ACR induces myelin damage, which in turn causes neurological dysfunction. Therefore, we established a rutin intervention model to investigate the protective effect of Rut on ACR-induced sciatic nerve injury in rats and its mechanism. The results showed that superoxide dismutase (SOD) activity and glutathione (GSH) content increased and lactate dehydrogenase (LDH) activity decreased in the middle and high dose groups of Rut compared with the ACR group, and the expression of Myelin basic protein (MBP), Extracellular-regulated kinase 1/2(ERK1/2), Phosphorylated extracellular regulated kinase 1/2 (P-ERK1/2), and Nuclear factor E-2-associated factor (Nrf2) was promoted in the Rut-protected group, which suggests that Rutin has a protective effect on ACR-induced sciatic nerve injury and that the mechanism of Rutin's protective effect is related to activation of the ERK1/2 pathway and alleviation of oxidative stress injury.

Effects of acrylamide exposure during pregnancy and lactation on the development of myelin sheath of corpus callosum in offspring rats

Acrylamide is an alkene known to induce neurotoxicity in humans and experimental animals. However, the effects of acrylamide on the development of myelin sheath are unclear. The present study was to explore the effects of acrylamide exposure during pregnancy and lactation on the development of myelin sheath in offspring rats. Four groups of thirty-two pregnant Sprague-Dawley rats were exposed to 0, 4.5, 9 and 18 mg/kg BW acrylamide by gavage from gestational day 15 to postnatal day 13. The corpus callosum of nine offspring rats per group were dissected in postpartum day 14. Structural changes and lipid contents in myelin sheaths were examined by transmission electron microscopy(TEM) and Luxol Fast Blue staining(LFB). The expression of MBP and PLP was evaluated by immunohistochemistry and Western blotting. TEM showed that the myelin sheaths in the 18 mg/kg group were disordered compared with control group. Luxol Fast Blue staining gradually decreased with increasing acrylamide maternal exposure. The immunohistochemistry and Western Blotting results showed that maternal exposure to acrylamide caused a decreasing trend in MBP and PLP in the corpus callosum of rats at postnatal day 14. Furthermore, these reduced protein levels may be neurodevelopmental toxicity's mechanism in response to maternal exposure to acrylamide.

Amelioration of neurobehavioral, biochemical, and morphological alterations associated with silver nanoparticles exposure by taurine in rats

The adverse effect of silver nanoparticles (AgNPs) on the nervous system is an emerging concern of public interest globally. Taurine, an essential amino acid required for neurogenesis in the nervous system, is well-documented to possess antioxidant, anti-inflammatory, and antiapoptotic activities. Yet, there is no report in the literature on the effect of taurine on neurotoxicity related to AgNPs exposure. Here, we investigated the neurobehavioral and biochemical responses associated with coexposure to AgNPs (200 µg/kg body weight) and taurine (50 and 100 mg/kg body weight) in rats. Locomotor incompetence, motor deficits, and anxiogenic-like behavior induced by AgNPs were significantly alleviated by both doses of taurine. Taurine administration enhanced exploratory behavior typified by increased track plot densities with diminished heat maps intensity in AgNPs-treated rats. Biochemical data indicated that the reduction in cerebral and cerebellar acetylcholinesterase activity, antioxidant enzyme activities, and glutathione level by AgNPs treatment were markedly upturned by both doses of taurine. The significant abatement in cerebral and cerebellar oxidative stress indices namely reactive oxygen and nitrogen species, hydrogen peroxide, and lipid peroxidation was evident in rats cotreated with AgNPs and taurine. Further, taurine administration abated nitric oxide and tumor necrosis factor-alpha levels cum myeloperoxidase and caspase-3 activities in AgNPs-treated rats. Amelioration of AgNPs-induced neurotoxicity by taurine was confirmed by histochemical staining and histomorphometry. In conclusion, taurine via attenuation of oxido-inflammatory stress and caspase-3 activation protected against neurotoxicity induced by AgNPs in rats.

Dietary acrylamide and incident osteoporotic fractures: an 8-year prospective cohort study

BACKGROUND

Acrylamide, a component of fried foods, has been associated with several negative health outcomes. However, the relationship between dietary acrylamide and osteoporotic fractures has been explored by a few cross-sectional studies.

AIMS

To investigate if dietary acrylamide is associated with the onset of fractures in North American participants at high risk/having knee osteoarthritis (OA), over 8 years of follow-up.

METHODS

A Cox's regression analysis, adjusted for baseline confounders was run and the data were reported as hazard ratios (HRs) and 95% confidence intervals (CIs). Dietary acrylamide intake was assessed at the baseline using a food frequency questionnaire and categorized in tertiles (T), whilst fractures' history was recorded using self-reported information.

RESULTS

Altogether, 4,436 participants were included. Compared to participants with lower acrylamide intake (T1; < 3,313 μg), those with a higher acrylamide intake (T3; > 10,180 μg) reported a significantly higher risk of any fracture (HR = 1.37; 95% CI 1.12-1.68; p for trend = 0.009), forearm (HR = 1.73; 95% CI 1.09-2.77; p for trend = 0.04), spine (HR = 2.21; 95% CI 1.14-4.31; p for trend = 0.04), and hip fracture (HR = 4.09; 95% CI 1.29-12.96; p for trend = 0.046).

CONCLUSIONS

Our study is the first to report that high dietary acrylamide may be associated with an increased risk of osteoporotic fractures.

Dietary acrylamide and physical performance tests: A cross-sectional analysis

BACKGROUND

Dietary acrylamide is found in certain foods, such as deep frying, baking and roasting, and is associated with higher inflammatory and oxidative stress parameters. The association between dietary acrylamide and physical performance has not yet been explored. The aim of the study was to investigate the relationship between dietary acrylamide intake and physical performance tests in a large cohort of North American individuals affected by knee osteoarthritis or at high risk for this condition.

METHODS

Dietary acrylamide intake was obtained through a food frequency questionnaire and reported in quartiles and as an increase in deciles. Physical performance was explored using the 20-meter usual pace test, the 400-meter walking distance, and the chair stands time. The association between dietary acrylamide and physical performance tests was explored using linear regression analysis, adjusted for potential confounders.

RESULTS

4,436 participants (2,578 women, mean age: 61.3) were enrolled. People in the highest quartile of dietary acrylamide reported significantly longer 20-meter walking (15.53±3.32 vs. 15.15±2.91 s), 400-meter walking (312±54 vs. 305±58 s) and chair stands (11.36±4.08 vs. 10.67±3.50 s) times than their counterparts in Q1. In adjusted linear regression analyses, each increase in one decile in dietary acrylamide was associated with a longer time in walking for 20 meters (beta = 0.032; 95%CI: 0.016-0.048; p = 0.04), 400 meters (beta = 0.048; 95%CI: 0.033-0.063; p = 0.002) and chair stands (beta = 0.016; 95%CI: 0.005-0.037; p = 0.04) times.

CONCLUSION

Higher dietary acrylamide intake was significantly associated with poor physical performance, also after accounting for potential confounders, suggesting a role for this food contaminant as a possible risk factor for sarcopenia.

CTRP6(C1q/Tumor Necrosis Factor (TNF)-related protein-6) alleviated the sevoflurane induced injury of mice central nervous system by promoting the expression of p-Akt (phosphorylated Akt)

Postoperative cognitive impairment and nervous system damage caused by anesthetics seriously affect patient’s postoperative recovery. Recent study has revealed that CTRP6 could alleviate apoptosis, inflammation and oxidative stress of nerve cells, thereby relieving nervous system damage induced by cerebral ischemia reperfusion. However, whether CTRP6 could relieve sevoflurane induced central nervous system injury is unclear. We stimulated C57BL/6 mice with sevoflurane and injected CTRP6 overexpression adenovirus vector. Next, H&E staining and TUNEL assays were performed to examine the effect of CTRP6 on sevoflurane induced injury of central nervous system. Finally, we isolated primary nerve cells of hippocampus. Flow cytometry and commercial kits were used for the detection of apoptosis and ROS levels of these cells. Western blotting was used for the detection of the expression level of p-Akt in central nervous tissues and primary cells. Results showed that sevoflurane induced injury and apoptosis of central nervous tissues. Overexpression of CTRP6 relieved apoptosis and injury of these tissues. CTRP6 inhibited the expression of cleaved caspase-3 and cleaved PARP in these tissues. Sevoflurane promoted apoptosis of primary cells and enhanced the expression of ROS and MDA in these cells. Overexpression of CTRP6 alleviated apoptosis and suppressed production of ROS and MDA in these cells. In addition, CTRP6 also enhanced the expression of p-Akt in primary cells. Taken together, our results suggested that CTRP6 relieved sevoflurane induced injury of central nervous tissues by promoting the expression of p-Akt. Therefore, the targeted drug of CTRP6 should be explored for the remission of these symptoms.

Mechanisms of peripheral neurotoxicity associated with four chemotherapy drugs using human induced pluripotent stem cell-derived peripheral neurons

The awareness of the long-term toxicities of cancer survivors after chemotherapy treatment has been gradually strengthened as the population of cancer survivors grows. Generally, chemotherapy-induced peripheral neurotoxicity (CIPN) is studied by animal models which are not only expensive and time-consuming, but also species-specific differences. The generation of human induced pluripotent stem cells (hiPSCs) and differentiation of peripheral neurons have provided an in vitro model to elucidate the risk of CIPN. Here, we developed a drug-induced peripheral neurotoxicity model using hiPSC-derived peripheral neurons (hiPSC-PNs) to study the mechanisms of different chemotherapeutic agents on neuronal viability using LDH assay, a cell apoptosis assay determined by caspase 3/7 activation, neurite outgrowth, ion channel expression and neurotransmitter release following treatment of cisplatin, bortezomib, ixabepilone, or pomalidomide. Our data showed that the multiple endpoints of the hiPSC-PNs model had different sensitivity to various chemotherapeutic agents. Furthermore, the chemotherapeutics separated cell viability from the decrease in neurite lengthand changed levels of ion channels and neurotransmitters to a certain extent. Thus, we study the mechanisms of peripheral neurotoxicity induced by chemotherapeutic agents through changes in these indicators.

Taurine ameliorates axonal damage in sciatic nerve of diabetic rats and high glucose exposed DRG neuron by PI3K/Akt/mTOR-dependent pathway

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes and axonopathy is its main pathological feature. Previous studies suggested an advantage of taurine against diabetes. However, there are few reports which study the effect of taurine against axonopathy. In this study, we confirmed that taurine significantly decreased blood glucose level, mitigated insulin resistance and improved dysfunctional nerve conduction in diabetic rats. Taurine corrected damaged axonal morphology of sciatic nerve in diabetic rats and induced axon outgrowth of Dorsal root ganglion (DRG) neurons exposed to high glucose. Taurine up-regulated phosphorylation levels of PI3K, Akt, and mTOR in sciatic nerve of diabetic rats and DRG neurons exposed to high glucose. However, Akt and mTOR inhibitors (MK-2206 and Rapamycin) blocked the effect of taurine on improving axonal damage. These results indicate that taurine ameliorates axonal damage in sciatic nerve of diabetic rats by activating PI3K/Akt/mTOR signal pathway. Our findings provide taurine as a potential candidate for axonopathy and a new evidence for elucidating protective mechanism of taurine on DPN.