Here we present a protocol to isolate mouse pancreatic islet cells for screening the ROS inductions by the xenobiotics in order to identify the potential diabetogenic xenobiotic chemicals.
Exposure to certain environmental chemicals in human and animals has been found to cause cellular damage of the pancreatic β cells which will lead to the development of type 2 diabetes mellitus (T2DM). Although the mechanisms for the chemical-induced β cell damage were unclear and likely to be complex, one recurring finding is that these chemicals induce oxidative stress leading to the generation of excessive reactive oxygen species (ROS) which induce damage to the β cell. To identify potential diabetogenic environmental chemicals, we isolated pancreatic islet cells from C57BL/6 mice and cultured islet cells in 96-well cell culture plates; then, the islet cells were dosed with chemicals and the ROS generation was detected by 2′,7′-dichlorofluorescein (DCFH-DA) fluorescent dye. Using this method, we found that bisphenol A (BPA), Benzo[a]pyrene (BaP), and polychlorinated biphenyls (PCBs), could induce high levels of ROS, suggesting that they may potentially induce damage in islet cells. This method should be useful for screening diabetogenic xenobiotics. In addition, the cultured islet cells may also be adapted for in vitro analysis of chemical-induced toxicity in pancreatic cells.
Increases in the prevalence of T2DM have become a global health crisis in recent years posing a serious threat to public health1. Many factors have been found to be causally linked to the development of T2DM, among which, recurring findings suggest that one common convergent point for these factors is the induction of oxidative stress which leads to the generation of excessive ROS2,3.
A wide spectrum of environmental chemicals including PCBs, dioxins, and BaP has been found to induce oxidative stress, which may impair the function of pancreatic β cells and lead to insulin resistance and T2DM4. Although the physiological level of ROS plays an important role in cellular functions, exposure to ROS that exceeds the capacity of the antioxidant system results in the damage to cells/tissues and leads to diseases5. Pancreatic β cells express a low level of antioxidant enzyme, and thus are a sensitive target for the oxidative stress-mediated damage6,7. Chronic exposure to high levels of ROS has been shown to cause stress-induced pancreatic cell dysfunction5 as well as insulin resistance in the liver and adipose tissue8.
The overall goal of this project is to develop a cell-based assay to screen chemicals for their diabetogenic potentials based on their induction of ROS in pancreatic cells. The pancreas lacks metabolic detoxification and is a sensitive target for xenobiotic-induced damage6,7. Therefore, by directly measuring the ROS generated in the pancreatic cells, this assay should provide a direct approximation of the chemical-induced injury in the pancreas. To develop this method, we isolated mouse pancreatic islets, cultured the isolated islet under cell culture condition with chemicals, and utilized the chemical-induced ROS generation as the readout. This procedure is simple and effective in identifying ROS-inducing chemicals in the isolated islet; it can be further developed for investigation of the mechanisms of toxicity that are specific to the pancreas in vitro.
Accumulating evidence suggests that exposure to environmental chemicals plays an important role in the development of T2DM. Xenobiotics-induced ROS has been recognized as a potential etiological factor contributing to the development of T2DM. Humans are exposed to a wide range of xenobiotic chemicals and there is a great need for novel research techniques to effectively identify the pancreatic toxicants and to investigate the mechanism of toxicity specific to the pancreatic cells.
In this stud…
The authors have nothing to disclose.
This work was supported by a pilot project grant from CREH center sponsored by NIEHS and by National Natural Science Foundation of China (No. 31572626).
10×Hank’s balanced salt solution | GIBCO | 14185-052 | |
Collagenase Type 4 | Worthington Biochemical Corporation | CLS-4 | |
polysucrose/sodium diatrizoate solution | Sigma | 10771 | |
2’,7’-dichlorofluorescein (DCFH-DA) | Sigma | D6883-50MG | |
fluorescence microplate reader | Biotek | ||
L-glutamine | Sigma | G8540-25G | |
streptomycin | GIBCO | 15140148 | |
FBS | GIBCO | 26140079 | |
RPMI 1640 | GIBCO | 11875-085 | |
avertin | Sigma | T48402-25G | |
Rat/Mouse Insulin ELISA Kit | Millipore | EZRMI-13K | |
Centrifuge | Sorval | Sorval RT7 | for 96-well plate centrifuge |
Microplate reader | Biotek | Epoch 2 | for fluorescence reading |