scholarly journals The neuroprotective action of dexmedetomidine on apoptosis, calcium entry and oxidative stress in cerebral ischemia-induced rats: Contribution of TRPM2 and TRPV1 channels

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Hatice Akpınar ◽  
Mustafa Nazıroğlu ◽  
İshak Suat Övey ◽  
Bilal Çiğ ◽  
Orhan Akpınar

Abstract Dexmedetomidine (DEX) may act as an antioxidant through regulation of TRPM2 and TRPV1 channel activations in the neurons by reducing cerebral ischemia-induced oxidative stress and apoptosis. The neuroprotective roles of DEX were tested on cerebral ischemia (ISC) in the cultures of rat primary hippocampal and DRG neurons. Fifty-six rats were divided into five groups. A placebo was given to control, sham control, and ISC groups, respectively. In the third group, ISC was induced. The DEX and ISC+DEX groups received intraperitoneal DEX (40 μg/kg) 3, 24, and 48 hours after ISC induction. DEX effectively reversed capsaicin and cumene hydroperoxide/ADP-ribose-induced TRPV1 and TRPM2 densities and cytosolic calcium ion accumulation in the neurons, respectively. In addition, DEX completely reduced ISC-induced oxidative toxicity and apoptosis through intracellular reactive oxygen species production and depolarization of mitochondrial membrane. The DEX and ISC+DEX treatments also decreased the expression levels of caspase 3, caspase 9, and poly (ADP-ribose) polymerase in the hippocampus and DRG. In conclusion, the current results are the first to demonstrate the molecular level effects of DEX on TRPM2 and TRPV1 activation. Therefore, DEX can have remarkable neuroprotective impairment effects in the hippocampus and DRG of ISC-induced rats.

2021 ◽  
pp. 096032712110361
Author(s):  
Hai-Tao Zhang ◽  
Xi-Zeng Wang ◽  
Qing-Mei Zhang ◽  
Han Zhao

Objective To explore the mechanism of chromobox 7 (CBX7)-mediated nuclear factor E2-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1) signaling pathway in the cerebral ischemia/reperfusion (I/R) injury. Methods The experimental wild-type (WT) and CBX7-/- mice were used to establish cerebral I/R models using the middle cerebral artery occlusion (MCAO) surgery to determine CBX7 levels at different time points after MCAO injury. For all mice, neurological behavior, infarct size, water content, and oxidative stress–related indicators were determined, and transferase (TdT)-mediated dUTP-biotin nick-end labeling (terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL)) staining method was employed to observe cell apoptosis, while Western blot to measure the expression of CBX7 and Nrf/HO-1 pathway-related proteins. Results At 6 h, 12 h, 24 h, 3 days, and 7 days after mice with MCAO, CBX7 expression was gradually up-regulated and the peak level was reached at 24 h. Mice in the WT + MCAO group had increased infarct size, with significant increases in the modified neurological severity scores and water content in the brain, as well as the quantity of TUNEL-positive cells. For the oxidative stress-indicators, an increase was seen in the content of MDA (malondial dehyde), but the activity of SOD (superoxide dismutase) and content of GSH-PX (glutathione peroxidase) and CAT (catalase) were decreased; meanwhile, the protein expression of CBX7, HO-1, and nuclear Nrf2 was up-regulated, while the cytoplasmic Nrf2 was down-regulated. Moreover, CBX7 knockout attenuated I/R injury in mice. Conclusion Knockout of CBX7 may protect mice from cerebral I/R injury by reducing cell apoptosis and oxidative stress, possibly via activating the Nrf2/HO-1 pathway.


2018 ◽  
Vol 12 (10) ◽  
pp. 94-101
Author(s):  
M. Elshamy Amira ◽  
K. Gaafar Nagah ◽  
E. ElAshwah Nadia ◽  
A. Wagih Ayman ◽  
A. Shahba Abeer

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jing Wang ◽  
Zhichun Dong ◽  
Liyin Lou ◽  
Lijuan Yang ◽  
Jingying Qiu

At present, there are few reports concerning the relationship between miR-122 and diabetes. In addition, the effect of miR-122 on streptozotocin- (STZ-) induced oxidative damage in INS-1 cells remains unclear. The present study aimed to investigate the role and modulatory mechanisms involving miR-122 in diabetes. STZ was used to induce INS-1 cell damage. Reverse transcription-quantitative PCR was used to investigate the expression of miR-122. A TUNEL cell apoptosis detection kit was used to detect apoptosis. Intracellular ROS levels were determined using dichlorofluorescein-diacetate. The activities of insulin secretion, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-px) were measured using ELISA kits. Western blotting was used to measure the expression levels of Bax, Bcl-2, PI3K, p-PI3K, caspase-3 and caspase-9, cleaved-caspase-3 and cleaved-caspase-9, AKT, and p-AKT. Then, LY294002 (LY, PI3K inhibitor) was used to treat INS-1 cells, and oxidative stress and apoptosis were measured. The results showed that STZ-induced inhibitory effects on insulin secretion were mitigated by miR-122 inhibitor, and the activities of SOD, CAT, and GSH-px were also increased. Furthermore, miR-122 inhibitor inhibited apoptosis and oxidative stress in STZ-induced INS-1 cells. Finally, the addition of LY increased insulin levels; reduced the activities of SOD, CAT, and GSH-px; and promoted apoptosis in STZ-induced INS-1 cells. In conclusion, interference with miR-122 can inhibit oxidative stress and apoptosis in STZ-induced INS-1 cells, involving a mechanism of action related to the PI3K/AKT pathway.


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