Carvacrol protects the ARPE19 retinal pigment epithelial cells against high glucose-induced oxidative stress, apoptosis, and inflammation by suppressing the TRPM2 channel signaling pathways.
Graefes Arch Clin Exp Ophthalmol 2022;
260:2567-2583. [PMID:
35704089 DOI:
10.1007/s00417-022-05731-5]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 05/20/2022] [Accepted: 06/07/2022] [Indexed: 11/04/2022] Open
Abstract
PURPOSE
The concentration of plasma high glucose (HGu) in diabetes mellitus (DM) induces the retinal pigment epithelial cell (ARPE19) death via the increase of inflammation, cytosolic (cytROS), and mitochondrial (mitROS) free oxygen radical generations. Transient potential melastatin 2 (TRPM2) cation channel is stimulated by cytROS and mitROS. Hence, the cytROS and mitROS-mediated excessive Ca2+ influxes via the stimulation of TRPM2 channel cause to the induction of DM-mediated retina oxidative cytotoxicity. Because of the antioxidant role of carvacrol (CRV), it may modulate oxidative cytotoxicity via the attenuation of TRPM2 in the ARPE19. We aimed to investigate the modulator action of CRV treatment on the HGu-mediated TRPM2 stimulation, oxidative stress, and apoptosis in the ARPE19 cell model.
MATERIAL AND METHODS
The ARPE19 cells were divided into four groups as normal glucose (NGu), NGu + Carv, HGu, and HGu + CRV.
RESULTS
The levels of cell death (propidium iodide/Hoechst rate) and apoptosis markers (caspases 3, 8, and 9), cytokine generations (IL-1β and TNF-α), ROS productions (cytROS, mitROS, and lipid peroxidation), TRPM2 currents, and intracellular free Ca2+ (Fluo/3) were increased in the HGu group after the stimulations of hydrogen peroxide and ADP-ribose, although their levels were diminished via upregulation of glutathione and glutathione peroxidase by the treatments of CRV and TRPM2 blockers.
CONCLUSION
Current results confirmed that the HGu-induced overload Ca2+ influx and oxidative retinal toxicity in the ARPE19 cells were induced by the stimulation of TRPM2, although they were modulated via the inhibition of TRPM2 by CRV. CRV may be noted as a potential therapeutic antioxidant to the TRPM2 activation-mediated retinal oxidative injury.
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