Hydrogen-rich water attenuates oxidative stress in rats with traumatic brain injury via Nrf2 pathway

Background: Several studies have recently found that oxidative stress plays a pivotal role in the pathogenesis of traumatic brain injury (TBI) and may represent a target in TBI treatment. Hydrogen-rich water was recently shown to exert neuroprotective effects in various neurological diseases through its antioxidant properties. However, the mechanisms underlying its effects in TBI are not clearly understood. The purpose of our study was to evaluate the neuroprotective role of hydrogen-rich water in rats with TBI and to elucidate the possible mechanisms underlying its effects. Materials and methods: The TBI model was constructed according to the modified Feeney weight-drop method. In part 1 of the experiment, we measured oxidative stress levels by observing the changes in catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) expressions. We also evaluated nuclear factor erythroid 2-related factor 2 (Nrf2) levels to determine the role of the protein in the neuroprotective effects against TBI. In part 2, we verified the neuroprotective effects of hydrogen-rich water in TBI and observed its effects on Nrf2. All the experimental rats were divided into sham group, TBI group, and TBI + hydrogen-rich water-treated (TBI + HW) group. We randomly chose 20 rats from each group and recorded their 7-d survival rates. Modified neurological severity scores were recorded from an additional six rats per group, which were then sacrificed 24 h after testing. Spectrophotometry was used to measure GPx, CAT, and MDA levels, whereas western blotting, reverse transcription polymerase chain reaction, and immunohistochemistry were used to measure the expression of Nrf2 and downstream factors like heme oxygenase 1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). Results: GPx and CAT activity was significantly decreased, and MDA content was increased in the TBI group compared with the sham group at 6 h after TBI. MDA content peaked at 24 h after TBI. Nrf2 nucleoprotein levels were upregulated in the TBI group compared with the sham group and peaked at 24 h after TBI; however, no significant changes in Nrf2 mRNA levels were noted after TBI. Hydrogen-rich water administration significantly increased 7-d survival rates, reduced neurologic deficits, and lowered intracellular oxidative stress levels. Moreover, hydrogen-rich water caused Nrf2 to enter the cell nucleus, which resulted in increases in the expression of downstream factors such as HO-1 and NQO1. Conclusions: Our results indicate that hydrogen-rich water has neuroprotective effects against TBI by reducing oxidative stress and activating the Nrf2 pathway.

Effect of hydrogen-rich water on the chondriosome damage and cytokines in brain tissue of rats with traumatic brain injury

Objective: To observe the effect of hydrogen-rich water on the chondriosome damage and cytokines change in brain tissue of rats with traumatic brain injury (TBI). Methods: Fifty-four health male Sprague-Dawley (SD) rats were divided into three groups by random number table: sham group, trauma group (TBI group), and trauma+hydrogen-rich water group (TBI+HW group), the rats in each group were subdivided into 1, 3 and 7 days subgroups according to the time points after trauma, with 6 rats in each subgroup. The TBI model was reproduced by using a modified Feency method for free fall impact, and the rats in sham group were not given brain impact after craniotomy. The rats in TBI+HW group were given intraperitoneal injection of hydrogen-rich water (5 mL/kg) after TBI model reproduction, and then once a day until being sacrificed; and the rats in sham group and TBI group were given the same amount of normal saline. The neurological severity scores (NSS) for neurologic deficits were calculated at corresponding time points, and then the rats were sacrificed to harvest brain tissue at 3 mm around lesion boundary. The cytokines including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were determined by enzyme linked immunosorbent assay (ELISA); the protein expressions of Bax, Bcl-2 were determined by Western Blot; the RFU of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and mitochondrial membrane permeability (MPTP) were determined by fluorescence and enzyme sign method. Results: TBI and TBI+HW groups appeared obvious neurologic damage after injury in rats. NSS scores in TBI and TBI+HW groups showed a decreased tendency with time prolongation after TBI. NSS scores in TBI+HW group at 3 days and 7 days were significantly lower than those of TBI group (NSS score: 9.67±0.82 vs. 11.17±1.17, 6.83±0.75 vs. 8.50±1.04, both P < 0.05). Compared with sham group, the expressions of TNF-α, IL-1β, RFU of ROS in chondriosome, protein expression of Bax in brain tissue in TBI group and TBI+HW group were significantly increased, peaked at 1 day, then they gradually declined. Each time point of RFU of MMP, MPTP in chondriosome and protein expression of Bcl-2 were significantly decreased, and gradually increased after one-day valley value. Compared with TBI group, the expressions of TNF-α, IL-1β, RFU of ROS in chondriosome and protein expression of Bax in brain tissue were all declined at corresponding time points [TNF-α (ng/L): 54.14±1.11 vs. 81.49±2.76, IL-1β (ng/L): 74.53±1.75 vs. 119.44±3.56, ROS (RFU): 92.30±2.46 vs. 121.33±6.57, Bax: 0.89±0.01 vs. 1.10±0.01, all P < 0.01]; RFU of MMP, MPTP in chondriosome and the protein expression of Bcl-2 were all increased at corresponding time points [MMP (RFU): 99.28±3.97 vs. 74.72±3.00, MPTP (RFU): 188.82±4.44 vs. 160.01±2.04, Bcl-2: 0.52±0.02 vs. 0.30±0.02, all P < 0.01]. Conclusions: The high expressions of cytokines and chondriosome damage were involved in the early TBI. Early treatment with an intraperitoneally injection of hydrogen-rich water can reduce chondriosome damage and inflammation factor release, reduce the nerve cell apoptosis after TBI, and protect brain function.