Evaluating the effect of diallyl sulfide on regulation of inflammatory mRNA expression in 3T3L1 adipocytes and RAW 264.7 macrophages during ethanol treatment.

Diallyl sulfide (DAS) has been studied extensively for its alleged role as an anticancer and protective agent. Alcohol influences and effects on human health have been extensively studied. However, investigations toward developing and testing therapeutic agents that can reduce the tissue injury caused by ethanol are scarce. In this backdrop, this study was designed to explore the potential effect of DAS in reducing alcohol induced damage of 3T3L1 adipocytes and RAW 264.7 macrophages. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay was performed to determine the DAS effect on cell viability. Reactive oxygen species (ROS) production was assessed by flow cytometer. Expression of inflammatory genes was studied by the qRT-PCR method. Our study results showed that DAS at concentrations less than 200 µM was not toxic to the cells and the viability of ethanol-exposed 3T3L1 adipocyte cells was found to be significantly increased when ethanol-exposed cells were treated with DAS. Further, treatment of ethanol-exposed 3T3L1 cells with 100 µM DAS for 24 h was found to reduce ethanol induced ROS production, expression of pro-inflammatory cytokines, and enhance anti-inflammatory cytokine production in the cells. Also, 100 µM DAS was found to increase the expression of M2 phenotype-specific genes in ethanol-exposed RAW 264.7 macrophage cells. Further, 100 µM DAS also improved the levels of lipid accumulation in 3T3L1 adipocytes that was down-regulated by ethanol exposure. Taken together, our study results imply that DAS may be effective in reducing ethanol induced injury of cells thereby suggesting its potential to be used in drug formulations.

Protective Effects of Diallyl Sulfide Against Ethanol-Induced Injury in Rat Adipose Tissue and Primary Human Adipocytes.

BACKGROUND: Alcohol consumption is the fourth leading cause of death and disability worldwide. Several cellular pathways contribute to alcohol-mediated tissue injury. Adipose tissue apart from functioning as an endocrine organ secretes several hormones and cytokines known as adipokines that are known to play a significant role in alcohol-induced tissue damage. This study was designed to test the efficacy of diallyl sulfide (DAS) in regulating the alcohol-induced outcomes on adipose tissue. METHODS: Male Wistar rats were fed with 36% Lieber-DeCarli liquid diet containing ethanol (EtOH) for 4 weeks. Control rats were pair-fed with isocaloric diet containing maltodextrin instead of EtOH. During the last week of feeding protocol, the EtOH-fed rat group was given 200 mg/kg body weight of DAS through diet. We also studied DAS effect on isolated human primary adipocytes. Viability of human primary adipocytes on DAS treatment was assessed by MTT assay. Malondialdehyde (MDA), a marker of oxidative stress, was measured by HPLC and the thiobarbituric acid method. Expression of inflammatory genes and lipogenic genes was studied by qRT-PCR and Western blotting. Serum inflammatory gene expression was studied by ELISA. RESULTS: Our study results showed that DAS could alleviate EtOH-induced expression levels of proinflammatory and endoplasmic reticulum (ER) stress genes and improve adipose tissue mass and adipocyte morphology in male Wistar rats fed Lieber-DeCarli diet containing 6% EtOH. Further, we showed that DAS reduced the expression of lipogenic genes and improved lipid accumulation and adipocyte mass in human primary adipocytes treated with EtOH. Subsequently, we also showed that oxidative stress, as measured by the changes in MDA levels, was reduced in both male Wistar rats and human primary adipocytes treated with EtOH plus DAS. CONCLUSIONS: Our study results prove that DAS is effective in ameliorating EtOH-induced damage to adipose tissue as evidenced by the reduction brought about by DAS in oxidative stress, ER stress, and proinflammatory gene expression levels. DAS treatment also regulated lipogenic gene expression levels, thereby reducing free fatty acid release. In conclusion, this study has clinical implications with respect to alcohol-induced adipose tissue injury among alcohol users.

Effect of alcohol on adipose tissue: a review on ethanol mediated adipose tissue injury.

BACKGROUND: Alcohol consumption has been in existence in the world for many centuries and it is the major cause of death and injury worldwide. Alcoholic liver disease (ALD) is caused due to excess and chronic alcohol intake. Studies across the globe have identified several pathways leading to ALD. Adipose tissue which has been considered as an energy storage organ is also found to play a major role in ALD progression by secreting hormones and cytokines known as adipokines or adipocytokines. Ethanol affects the metabolic and innate immune activities of adipose tissue contributing to alcohol-induced injury of the tissues. OBJECTIVE: We aimed at 1) summarizing the metabolism and progression of ALD 2) summarizing about the structure and effect of ethanol induced oxidative stress on adipose tissue 3) reviewing the available data on the effect of ethanol on adipose tissue mass and adipokine secretion in both rodent models and alcoholic patients. METHODS: The article is summarized based on the original literature and reviews in studying the effect of ethanol on adipose tissue. RESULTS: Studies on alcoholic patients and rodent models has shown that chronic ethanol consumption reduces adipose tissue mass and causes CYP2E1 mediated oxidative stress and inflammation of adipose tissue. Further hyperlipolysis is observed in adipose tissue that leads to excess fatty acid release that gets transported and deposited in the liver resulting in hepatic steatosis. CONCLUSION: Studies show that adipose tissue plays a major role in the progression of ALD. So understanding of the mechanisms linking ethanol induced adipose tissue injury with ALD progression would help us in identifying potential therapeutic targets.