Effect of hydrogen-rich water on the CD34 expression in lesion boundary brain tissue of rats with traumatic brain injury

Abstract:

Objective: To observe the effect of hydrogen-rich water on the CD34 expression and angiogenesis in lesion boundary brain tissue of rats with traumatic brain injury (TBI).

Methods: A total of 54 adult male Sprague-Dawley (SD) rats were divided into three groups by random number table: namely sham-operated group (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 for brain tissue at 3 mm around lesion boundary. After hematoxylin-eosin (HE) staining, the pathological changes in lesion boundary brain tissue were observed under light microscope. The expression of CD34+ cells was observed by immunohistochemical analysis, which markers were used to count the newborn blood capillary sprouts around the traumatic brain tissue. The protein expression of CD34 was determined by Western Blot.

Results: NSS scores at all time points in sham group were 0. NSS scores in TBI and TBI+HW groups showed a decreased tendency with time prolongation after TBI, which showed more significant in TBI+HW group, NSS scores at 3 days and 7 days were significantly lower than those of TBI group (3 day: 8.67±0.52 vs. 11.56±1.94, 7 days: 7.33±0.52 vs. 8.17±0.98, both P < 0.05). Under light microscope, the brain tissue of rats in sham group was normal. After injury, pathological changes in lesion boundary brain tissue in TBI group were characterized by obvious hemorrhagic necrosis, severe brain edema, a large number of degeneration and necrosis of nerve cells and inflammatory cell infiltration, and the pathological changes were more obvious at 3 days. The edema area in TBI+HW group was slightly smaller than that of TBI group, and the surrounding edema was slightly reduced. It was shown by immunohistochemistry that only a very small number of neoformative capillaries were found in sham group. The number of neoformative capillaries in lesion boundary brain tissue was gradually increased with time prolongation in TBI group. The number of neoformative capillaries in TBI+HW group was more significantly, which was significantly higher than that of TBI group at 3 days and 7 days after injury (cells/HP: 10.59±1.88 vs. 8.61±1.22 at 3 days, 23.20±3.16 vs. 17.01±2.64 at 7 days, both P < 0.05). It was shown by Western Blot that the expression of CD34 protein at all time points in TBI group was significantly increased as compared with that of sham group. The expression of CD34 protein at 1 day and 3 days in TBI+HW group was slightly increased as compared with that of TBI group without significant difference, but it was significantly up-regulated at 7 days after injury, which was significantly higher than that of TBI group (gray value: 1.36±0.36 vs. 0.74±0.08, P < 0.05). Conclusions: Hydrogen-rich water promote CD34+ cells home to the site of injured tissue in rats with TBI, is involved in angiogenesis, and improve clinical outcomes during brain functional recovery.