Vitamin E Can Ameliorate Oxidative Damage of Ovine Hepatocytes In Vitro by Regulating Genes Expression Associated with Apoptosis and Pyroptosis, but Not Ferroptosis.

Luyang Jian,Yuefeng Gao,Bo Wang,Bing Wang,Yanghua Qu,Ying Xue,Shuanghong Li,Heqiong Li,Hailing Luo,Zhen Li

doi:10.3390/molecules26154520

Abstract

(1) Background: the current research was conducted to investigate the potential non-antioxidant roles of vitamin E in the protection of hepatocysts from oxidative damage. (2) Methods: primary sheep hepatocytes were cultured and exposed to 200, 400, 600, or 800 μmol/L hydrogen peroxide, while their viability was assessed using a CCK-8 kit. Then, cells were treated with 400 μmol/L hydrogen peroxide following a pretreatment with 50, 100, 200, 400, and 800 μmol/L vitamin E and their intracellular ROS levels were determined by means of the DCF-DA assay. RNA-seq, verified by qRT-PCR, was conducted thereafter: non-treated control (C1); cells treated with 400 μmol/L hydrogen peroxide (C2); and C2 plus a pretreatment with 100 μmol/L vitamin E (T1). (3) Results: the 200–800 μmol/L hydrogen peroxide caused significant cell death, while 50, 100, and 200 μmol/L vitamin E pretreatment significantly improved the survival rate of hepatocytes. ROS content in the cells pretreated with vitamin E was significantly lower than that in the control group and hydrogen-peroxide-treated group, especially in those pretreated with 100 μmol/L vitamin E. The differentially expressed genes (DEGs) concerning cell death involved in apoptosis (RIPK1, TLR7, CASP8, and CASP8AP2), pyroptosis (NLRP3, IL-1β, and IRAK2), and ferroptosis (TFRC and PTGS2). The abundances of IL-1β, IRAK2, NLRP3, CASP8, CASP8AP2, RIPK1, and TLR7 were significantly increased in the C1 group and decreased in T1 group, while TFRC and PTGS2 were increased in T1 group. (4) Conclusions: oxidative stress induced by hydrogen peroxide caused cellular damage and death in sheep hepatocytes. Pretreatment with vitamin E effectively reduced intracellular ROS levels and protected the hepatocytes from cell death by regulating gene expression associated with apoptosis (RIPK1, TLR7, CASP8, and CASP8AP2) and pyroptosis (NLRP3, IL-1β, and IRAK2), but not ferroptosis (TFRC and PTGS2).

Highlights

Vitamin E was first described as a compound that was essential for the reproduction of rats [1] and was widely recognized as a lipid-soluble, chain-breaking antioxidant that prevents the cyclic propagation of lipid peroxidation [2,3]
The differentially expressed genes (DEGs) concerning cell death involved in apoptosis (RIPK1, TLR7, CASP8, and CASP8AP2), pyroptosis (NLRP3, IL-1β, and IRAK2), and ferroptosis (TFRC and PTGS2)
Treatment of sheep hepatocytes with H2 O2 at concentrations ranging from 200 to 800 μmol/L for 6 h led to a significant decrease in cell viability in a dose-dependent manner (Figure 1)

Summary

Introduction

Vitamin E was first described as a compound that was essential for the reproduction of rats [1] and was widely recognized as a lipid-soluble, chain-breaking antioxidant that prevents the cyclic propagation of lipid peroxidation [2,3]. By means of its antioxidant properties, vitamin E is able to mitigate the harmful effects of oxidative stress on the male reproductive organ as well as spermatogenesis [4]. High levels of dietary vitamin E supplementation could significantly increase the expression (both at the mRNA and protein levels) of oxidative enzyme-related genes, such as Glutathione peroxidase 3 and Glutathione S-transferase alpha 1, through its non-antioxidant properties [5]. While it is well-known that vitamin E eliminates the harmful effects of oxidative stress, few studies have focused on its potential non-antioxidant function in cell protection systematically.

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Conclusion