Palmitic acid-induced lipotoxicity and protection by (+)-catechin in rat cortical astrocytes.

Pharmacological reports : PR (2014-12-03)
Kar-Lok Wong, Yu-Ru Wu, Ka-Shun Cheng, Paul Chan, Chi-Wai Cheung, Dah-Yuu Lu, Tzu-Hui Su, Zhong-Min Liu, Yuk-Man Leung
RESUMEN

Astrocytes do not only maintain homeostasis of the extracellular milieu of the neurons, but also play an active role in modulating synaptic transmission. Palmitic acid (PA) is a saturated fatty acid which, when being excessive, is a significant risk factor for lipotoxicity. Activation of astrocytes by PA has been shown to cause neuronal inflammation and demyelination. However, direct damage by PA to astrocytes is relatively unexplored. The aim of this study was to identify the mechanism(s) of PA-induced cytotoxicity in rat cortical astrocytes and possible protection by (+)-catechin. Cytotoxicity and endoplasmic reticulum (ER) markers were assessed by MTT assay and Western blotting, respectively. Cytosolic Ca(2+) and mitochondrial membrane potential (MMP) were measured microfluorimetrically using fura-2 and rhodamine 123, respectively. Intracellular reactive oxygen species (ROS) production was assayed by the indicator 2'-7'-dichlorodihydrofluorescein diacetate. Exposure of astrocytes to 100μM PA for 24h resulted in apoptotic cell death. Whilst PA-induced cell death appeared to be unrelated to ER stress and perturbation in cytosolic Ca(2+) signaling, it was likely a result of ROS production and subsequent MMP collapse, since ascorbic acid (anti-oxidant, 100μM) prevented PA-induced MMP collapse and cell death. Co-treatment of astrocytes with (+)-catechin (300μM), an anti-oxidant found abundantly in green tea, significantly prevented PA-induced ROS production, MMP collapse and cell death. Our results suggest that PA-induced cytotoxicity in astrocytes may involve ROS generation and MMP collapse, which can be prevented by (+)-catechin.

MATERIALES
Referencia del producto
Marca
Descripción del producto

Sigma-Aldrich
L-Ascorbic acid, 99%
Sigma-Aldrich
L-Ascorbic acid, powder, suitable for cell culture, γ-irradiated
Sigma-Aldrich
Palmitic acid, ≥99%
Supelco
Ascorbic Acid, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
L-Ascorbic acid, BioXtra, ≥99.0%, crystalline
Sigma-Aldrich
L-Ascorbic acid, suitable for cell culture, suitable for plant cell culture, ≥98%
Sigma-Aldrich
L-Ascorbic acid, ACS reagent, ≥99%
Sigma-Aldrich
Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, ≥98% (TLC), powder
Sigma-Aldrich
L-Ascorbic acid, reagent grade, crystalline
Supelco
(+)-Catechin, analytical standard
Sigma-Aldrich
Palmitic acid, BioXtra, ≥99%
Supelco
Palmitic acid, analytical standard
Supelco
L-Ascorbic acid, analytical standard
Sigma-Aldrich
L-Ascorbic acid, puriss. p.a., ACS reagent, reag. ISO, Ph. Eur., 99.7-100.5% (oxidimetric)
USP
Ascorbic acid, United States Pharmacopeia (USP) Reference Standard
Supelco
Palmitic acid, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
L-Ascorbic acid, reagent grade
Ascorbic acid, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
L-Ascorbic acid, meets USP testing specifications
Sigma-Aldrich
Palmitic acid, ≥95%, FCC, FG
Supelco
L-Ascorbic acid, certified reference material, TraceCERT®
Sigma-Aldrich
L-Ascorbic acid, FCC, FG
Sigma-Aldrich
L-Ascorbic acid, puriss. p.a., ≥99.0% (RT)
Sigma-Aldrich
Cyclopiazonic acid from Penicillium cyclopium, ≥98% (HPLC), powder
Sigma-Aldrich
L-Ascorbic acid, BioUltra, ≥99.5% (RT)
Sigma-Aldrich
Palmitic acid, natural, 98%, FG
USP
Palmitic acid, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Palmitic acid, ≥98% palmitic acid basis (GC)
Palmitic acid, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
L-Ascorbic acid, tested according to Ph. Eur.