Background: Aquaporin 4 (AQP4), usually expressed at astrocytes end-feet, is a main component of the lymph-lymphatic system and promotes paravascular cerebrospinal fluid-interstitial fluid exchange. Moreover, angiotensin II type 1 (AT(1)) receptor affects amyloid beta (A beta) levels. This study aimed to detect the effect of AT, receptor deficiency on the blood-brain barrier (BBB) of traumatic brain injury (TBI) mice and the effect on A beta level and glial lymphatic circulation. Methods: TBI model was built using AT(1) receptor knockout mice (AT(1)-KO) and C57BL/6 mice (wild type, WT). BBB integrity was detected by Evans blue extravasation. The expression of the astrocytic water channel AQP4 and astrocyte activation were evaluated with immunofluorescence. The expressions of amyloid precursor protein (APP), junction protein zonula occludens protein-1 (ZO-1) and occludin in mice brain were detected by Western blot (WB). A beta levels were assayed by enzyme-linked immunosorbent assay (ELISA). Results: AT(1) receptor deficiency defended BBB integrity and rescued occludin and ZO-1 decrease in mice brain induced by TBI. AT(1)-KO mice had less increase of APP expression and A beta 1-42, A beta 1-40 levels compared to WT mice under TBI. Moreover, AT(1) receptor deficiency was found to significantly inhibit AQP4 depolarization after TBI. Conclusion: T-1 receptor deficiency attenuated TBI-induced impairments of BBB by rescuing tight junction proteins and inhibited AQP4 polarization, thus improving the function of glymphatic system to enhance interstitial A beta clearance in TBI mice brain.

BACKGROUND:Traumatic brain injury (TBI) is a common clinical condition caused by external force. Aquaporin-4 (AQP4) in astrocytes participates in the generation of cell swelling in TBI. METHODS:This research explored the effect of AQP4 gene silencing in a TBI rat model. A hydraulic craniocerebral trauma instrument was employed for establishing the TBI rat model. AQP4 expression in the brain was inhibited by the injection of AQP4 shRNA-lentiviral vector. The expression of relative genes was evaluated by Western blot and qRT-PCR. Neuronal apoptosis was analyzed by TUNEL assay. RESULTS:AQP4 shRNA treatment inhibited AQP4 expression in the brain of rats with TBI. AQP4 shRNA alleviated TBI-induced brain edema and neurological deficit in rats. Neuronal apoptosis and astrocyte activation in TBI rats were reduced by AQP4 silencing. CONCLUSION:This research demonstrated that AQP4 shRNA-induced silencing of AQP4 in the TBI rat model reduced the expression of AQP4 and GFAP, alleviated brain edema, neurological deficit, neuronal apoptosis and inhibited astrocyte activation.

Pyroptosis has been reported to contribute to the traumatic brain injury (TBI) process. Ac-FLTD-CMK is a newly synthesized pyroptosis inhibitor. However, whether Ac-FLTD-CMK inhibits pyroptosis and plays a neuroprotective role after TBI is unknown. The present study aimed to determine the effects of Ac-FLTD-CMK on TBI in a mouse model. Male C57BL/6 mice were randomly divided into sham, TBI + vehicle, and TBI + Ac-FLTD-CMK groups. TBI was induced using a weight-drop apparatus. Intraventricular injection of Ac-FLTD-CMK was performed 30 min after TBI. Caspase-1, caspase-11, gasdermin-D (GSDMD), and caspase-3 expression in the peri-contusional cortex were assessed by western blotting. Interleukin-1β (IL-1β) and interleukin-18 (IL-18) expression in the peri-contusional cortex were measured using ELISA. Behavioral experiments, brain water content, Evans blue extravasation, lactate dehydrogenase (LDH) release, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining were also performed. The results showed that Ac-FLTD-CMK administration significantly downregulated caspase-1 p20, caspase-11 p20, GSDMD N-terminal, IL-1β, and IL-18 expression; reduced LDH release; alleviated neuronal death; attenuated brain edema and blood-brain barrier damage; and improved neurobehavioral function. These findings indicate that Ac-FLTD-CMK treatment suppresses pyroptosis and protects mice against TBI.

Objective:To investigate the relationship between the origin of vertebral artery and the height of transverse foramen of cervical vertebra using three-dimensional CT angiography (CTA).Methods:The clinical data of 480 patients who underwent head, neck and upper chest CTA examinations from March 2017 to March 2019 at Department of Neurosurgery, the Second Hospital of Hebei Medical University were retrospectively analyzed. The images were transferred to the image post-processing workstation for bone and vascular reconstruction, and the origin and course of bilateral vertebral arteries and the height of the vertebral arteries entering the cervical vertebrae transverse foramen were documented. Patients with normal origin of the right vertebral artery were divided into groups C 4, C 5, and C 6 according to the height of vertebral artery entering transverse foramen of cervical vertebra. Ten cases were randomly selected from each group to measure the distance from the origin of right vertebral artery to the origin of right common carotid artery (L 1) and to the right thyroid cervical trunk (L 2). We calculated the relative position of the origin of vertebral artery with L1/(L 1+ L 2)×100%. Results:Among 480 patients, 457 cases (95.2%) had normal origins of bilateral vertebral arteries which were from the subclavian artery, and the other 23 cases (4.8%) had abnormal origins. Among them, the left vertebral artery originated from the aortic arch in 19 cases, and left vertebral artery originated from the left external carotid artery in 1 case; the right vertebral artery originated from the right common carotid artery in 3 cases, all of which were complicated with aberrant right subclavian artery. Among the 480 patients, 405 cases (84.4%) had bilateral vertebral arteries entering the C 6 transverse foramen. The remaining 75 (15.6%) had vertebral arteries entering the cervical transverse foramen with abnormal height, which was observed on the left side in 34 cases (left vertebral arteries entering transverse foramen of C 3, C 4, C 5, C 7 in 1 case, 4 cases, 24 cases and 4 cases respectively, and directly entering the foramen magnum in 1 case) and on the right side in 41 cases (right vertebral artery entering C 3, C 4 and C 5 in 1 case, 14 cases, 26 cases respectively). The height of vertebral artery entering transverse foramen of cervical vertebra was mostly abnormal when the origin of left vertebral artery was abnormal. In patients with abnormal vertebral artery origin, the left vertebral artery originating from the aortic arch accounted for the highest proportion (19/20), and most of the vertebral arteries entered the transverse foramen of cervical vertebra with abnormal height (18/19). The right vertebral artery originating from the right common carotid artery were complicated with aberrant right subclavian artery (3/3), and the height of vertebral artery entering transverse foramen of cervical vertebra was abnormal (3/3). In patients with normal vertebral artery origin, 96.7% (445/460) of left vertebral artery entered transverse foramen of cervical vertebra with normal height, and 92.0% (439/477) of the right vertebral artery entered transverse foramen of cervical vertebra with normal height. Comparison of patients with normal right vertebral artery origin in the 3 groups showed statistically significant differences in the relative position of the vertebral artery origin (C 4 group: 24.3±2.1 %, C 5 group: 47.9±6.6 %, and C 6 group: 77.7±1.7 %, H=20.178, P<0.001). Conclusions:In case of abnormal origins of vertebral arteries, the heights of vertebral arteries at the transverse foramen of cervical vertebra are mostly abnormal. When the relative position of origin of right vertebral artery is closer to the right common carotid artery, the height of right vertebral artery at the transverse foramen of cervical vertebra seems higher. When the relative origin of right vertebral artery is closer to the right thyroid cervical trunk, the height of right vertebral artery at the transverse foramen of cervical vertebra seems lower.

Background: The glymphatic pathway has been shown to be impaired in traumatic brain injury (TBI). Omega-3 polysaturated fatty acids (Omega-3, PUFAs) are involved in the clearance of amyloid-ß through the glymphatic system and this effect is Aquaporin-4 (AQP4) dependent. We hypothesize that Omega-3 PUFAs can alleviate neurological impairment in TBI by protecting the glymphatic pathway.Methods: We pretreated mice with Omega-3 PUFAs rich fish oil and introduced TBI in the mice. Neurological functions were assessed through the modified neurological severity score (mNSS) system and Rota-rod test. Aß42 levels and radioisotope clearance were examined to determine the function of glymphatic system. AQP4 protein and mRNA expressions and its polarity were examined in fish oil treated TBI mice or control mice. Finally, the integrity of blood-brain barrier was determined by Evans blue extravasation and measurement of tight junction proteins (ZO-1 and Occludin) levels.Results: TBI surgery induced significant neurological functional impairment, Omega-3 PUFAs attenuated TBI-induced neurological impairment, as evidenced by reduced mNSS, improved performance in the Rota-rod test. Furthermore, Omega-3 PUFAs improved glymphatic clearance after induction of TBI in mice, reduced Aß42 accumulation, partially restored the clearance of both 3H-mannitol and 14C-Inulin. Omega-3 PUFAs also suppressed AQP4 expression and partially prevented loss of AQP4 polarity in mice undergoing TBI. Finally, Omega-3 PUFAs protected mice from TBI induced blood-brain barrier disruption.Conclusion: Omaga-3 PUFAs attenuate neurological function by partially restoring the AQP4 dependent glymphatic system in mice with TBI.