Evaluation of sphingolipids in Wistar rats treated to prolonged and single oral doses of fumonisin b₁

Evaluation of the Individual and Combined Toxicity of Fumonisin Mycotoxins in Human Gastric Epithelial Cells

Fumonisin contaminates food and feed extensively throughout the world, causing chronic and acute toxicity in human and animals. Currently, studies on the toxicology of fumonisins mainly focus on fumonisin B1 (FB1). Considering that FB1, fumonisin B2 (FB2) and fumonisin B3 (FB3) could coexist in food and feed, a study regarding a single toxin, FB1, may not completely reflect the toxicity of fumonisin. The gastrointestinal tract is usually exposed to these dietary toxins. In our study, the human gastric epithelial cell line (GES-1) was used as in vitro model to evaluate the toxicity of fumonisin. Firstly, we found that they could cause a decrease in cell viability, and increase in membrane leakage, cell death and the induction of expression of markers for endoplasmic reticulum (ER) stress. Their toxicity potency rank is FB1 > FB2 >> FB3. The results also showed that the synergistic effect appeared in the combinations of FB1 + FB2 and FB1 + FB3. Nevertheless, the combinations of FB2 + FB3 and FB1 + FB2 + FB3 showed a synergistic effect at low concentration and an antagonistic effect at high concentration. We also found that myriocin (ISP-1) could alleviate the cytotoxicity induced by fumonisin in GES-1 cells. Finally, this study may help to determine or optimize the legal limits and risk assessment method of mycotoxins in food and feed and provide a potential method to block the fumonisin toxicity.

Isolation and Quantification of Sphingosine and Sphinganine from Rat Serum Revealed Gender Differences

Sphingolipids are an important group of lipids that play crucial roles in living cells, facilitating cell recognition, signal transduction and endocytosis. The concentration of sphingosine and some of its derivatives like sphinganine may serve as a biomarker for the diagnosis of sphingolipidoses or be used for further research into similar diseases. In this study, a sphingolipid extraction and a high resolution detection method specific for sphingosine and sphinganine was adapted and tested. Lipids were extracted from rats’ serum, coupled to o-phthalaldehyde and detected with a fluorescence detector after running through a silica gel column in a high performance liquid chromatography system. With this method, we analysed 20 male and 20 female rat serum samples and compared the concentrations of sphingosine and sphinganine. The results showed a significant difference between the sphingosine concentrations in the male and female rats. The sphingosine concentration in female rats was 805 ng/mL (standard deviation, SD ± 549), while that in males was significantly lower at (75 ng/mL (SD ± 40)). Furthermore, the sphingosine:sphinganine ratio was almost 15-fold higher in the females’ samples. The method presented here facilitates the accurate quantification of sphingosine and sphinganine concentrations down to 2.6 ng and 3.0 ng, respectively, and their ratio in small amounts of rat serum samples to study the sphingolipid metabolism and its potential modulation due to gene mutations or the effect of prevalent toxins.