scholarly journals Magnesium Sulfate Prevents Placental Ischemia-Induced Increases in Brain Water Content and Cerebrospinal Fluid Cytokines in Pregnant Rats

2016 ◽  
Vol 10 ◽  
Author(s):  
Linda W. Zhang ◽  
Junie P. Warrington
2015 ◽  
Vol 309 (11) ◽  
pp. R1425-R1431 ◽  
Author(s):  
Junie P. Warrington ◽  
Heather A. Drummond ◽  
Joey P. Granger ◽  
Michael J. Ryan

Cerebrovascular complications and increased risk of encephalopathies are characteristic of preeclampsia and contribute to 40% of preeclampsia/eclampsia-related deaths. Circulating tumor necrosis factor-α (TNF-α) is elevated in preeclamptic women, and infusion of TNF-α into pregnant rats mimics characteristics of preeclampsia. While this suggests that TNF-α has a mechanistic role to promote preeclampsia, the impact of TNF-α on the cerebral vasculature during pregnancy remains unclear. We tested the hypothesis that TNF-α contributes to cerebrovascular abnormalities during placental ischemia by first infusing TNF-α in pregnant rats (200 ng/day ip, from gestational day 14 to 19) at levels to mimic those reported in preeclamptic women. TNF-α increased mean arterial pressure (MAP, P < 0.05) and brain water content in the anterior cerebrum ( P < 0.05); however, TNF-α infusion had no effect on blood-brain barrier (BBB) permeability in the anterior cerebrum or posterior cerebrum. We then assessed the role of endogenous TNF-α in mediating these abnormalities in a model of placental ischemia induced by reducing uterine perfusion pressure followed by treatment with the soluble TNF-α receptor (etanercept, 0.8 mg/kg sc) on gestational day 18. Etanercept reduced placental ischemia-mediated increases in MAP, anterior brain water content ( P < 0.05), and BBB permeability (202 ± 44% in placental ischemic rats to 101 ± 28% of normal pregnant rats). Our results indicate that TNF-α mechanistically contributes to cerebral edema by increasing BBB permeability and is an underlying factor in the development of cerebrovascular abnormalities associated with preeclampsia complicated by placental ischemia.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Junie P Warrington ◽  
Fan Fan ◽  
Babbette B LaMarca ◽  
Ralf Dechend ◽  
Gerd Wallukat ◽  
...  

Placental ischemia, a characteristic feature of preeclampsia, leads to impaired cerebral blood flow (CBF) autoregulation, cerebral edema, and increased blood-brain barrier (BBB) permeability; however, the placental factors that contribute to these cerebral abnormalities are not clear. Agonistic autoantibodies to the angiotensin II type 1 receptor (AT1-AA) are increased in preeclamptic patients as well as in a rat model of preeclampsia induced by placental ischemia. In this study, we tested the hypothesis that AT1-AA mediates placental ischemia-induced cerebrovascular abnormalities. To determine whether the AT1-AA contributes to impaired CBF autoregulation, we infused purified rat AT1-AA into normal pregnant rats from gestational day (GD) 12 to 19 via mini-osmotic pumps and measured CBF using laser Doppler flowmetry on GD 19. Autoregulatory index increased from 0.7 to 1.0±0.2 in the AT1-AA infused group over the range of 120 to 160 mmHg compared to pregnant controls (0.3 to 0.5±0.1 over the same range of pressures, p<0.05) suggesting impaired CBF autoregulation. However, AT1-AA infusion did not affect brain water content at baseline blood pressures (104±2 mmHg in normal pregnant rats vs. 113±2 mmHg in AT1-AA infused rats, p<0.01). To determine the role of endogenous AT1-AA in mediating placental ischemia-induced cerebrovascular abnormalities, losartan (5 mg/kg/day), an AT1 receptor antagonist, was administered in the drinking water from GD 14 to 19. Losartan reduced anterior brain water content from 79.6±0.2% in placental ischemic rats to 79.2±0.1% (compared to 79.1±0.1% in normal pregnant untreated rats) and BBB permeability from 0.06±0.01 in placental ischemic rats to 0.03±0.03 (compared to 0.03±0.004 in normal pregnant untreated rats). These results indicate that impaired CBF autoregulation in response to placental ischemia is due, at least in part, to increases in circulating AT1-AA. While AT1-AA infusion, by itself, did not alter brain water content at baseline blood pressures, the beneficial effects of losartan in placental ischemic rats suggests that the renin-angiotensin system may interact with other placental factors to promote cerebral vascular changes common to preeclampsia.


2020 ◽  
Vol 12 (1) ◽  
pp. 001-008
Author(s):  
Ting Liu ◽  
Xing-Zhi Liao ◽  
Mai-Tao Zhou

Abstract Background Brain edema is one of the major causes of fatality and disability associated with injury and neurosurgical procedures. The goal of this study was to evaluate the effect of ulinastatin (UTI), a protease inhibitor, on astrocytes in a rat model of traumatic brain injury (TBI). Methodology A rat model of TBI was established. Animals were randomly divided into 2 groups – one group was treated with normal saline and the second group was treated with UTI (50,000 U/kg). The brain water content and permeability of the blood–brain barrier were assessed in the two groups along with a sham group (no TBI). Expression of the glial fibrillary acidic protein, endthelin-1 (ET-1), vascular endothelial growth factor (VEGF), and matrix metalloproteinase 9 (MMP-9) were measured by immunohistochemistry and western blot. Effect of UTI on ERK and PI3K/AKT signaling pathways was measured by western blot. Results UTI significantly decreased the brain water content and extravasation of the Evans blue dye. This attenuation was associated with decreased activation of the astrocytes and ET-1. UTI treatment decreased ERK and Akt activation and inhibited the expression of pro-inflammatory VEGF and MMP-9. Conclusion UTI can alleviate brain edema resulting from TBI by inhibiting astrocyte activation and ET-1 production.


2021 ◽  
pp. 1-9
Author(s):  
Qinhan Hou ◽  
Hongmou Chen ◽  
Quan Liu ◽  
Xianlei Yan

Traumatic brain injury (TBI) can induce neuronal apoptosis and neuroinflammation, resulting in substantial neuronal damage and behavioral disorders. Fibroblast growth factors (FGFs) have been shown to be critical mediators in tissue repair. However, the role of FGF10 in experimental TBI remains unknown. In this study, mice with TBI were established via weight-loss model and validated by increase of modified neurological severity scores (mNSS) and brain water content. Secondly, FGF10 levels were elevated in mice after TBI, whereas intraventricular injection of Ad-FGF10 decreased mNSS score and brain water content, indicating the remittance of neurological deficit and cerebral edema in TBI mice. In addition, neuronal damage could also be ameliorated by stereotactic injection of Ad-FGF10. Overexpression of FGF10 increased protein expression of Bcl-2, while it decreased Bax and cleaved caspase-3/PARP, and improved neuronal apoptosis in TBI mice. In addition, Ad-FGF10 relieved neuroinflammation induced by TBI and significantly reduced the level of interleukin 1β/6, tumor necrosis factor α, and monocyte chemoattractant protein-1. Moreover, Ad-FGF10 injection decreased the protein expression level of Toll-like receptor 4 (TLR4), MyD88, and phosphorylation of NF-κB (p-NF-κB), suggesting the inactivation of the TLR4/MyD88/NF-κB pathway. In conclusion, overexpression of FGF10 could ameliorate neurological deficit, neuronal apoptosis, and neuroinflammation through inhibition of the TLR4/MyD88/NF-κB pathway, providing a potential therapeutic strategy for brain injury in the future.


1988 ◽  
Vol 8 (1) ◽  
pp. 89-95 ◽  
Author(s):  
John J. Grome ◽  
Gerlinde Gojowczyk ◽  
Wolfgang Hofmann ◽  
David I. Graham

This study was carried out with a recently developed model of focal cerebral ischemia in the rat based on the photochemical induction of thrombotic stroke using the dye Rose Bengal. We examined the change in the volume of the lesion and brain water content, in separate groups of rats, at different times (1, 4, 24, 72, and 168 h) after the induction of the ischemic lesion. The volume of ischemic damage increased rapidly between 1 and 24 h after the ischemic insult and decreased between 24 and 168 h. The lesion at 168 h was significantly larger than that following 1 h of ischemia and similar to that obtained at 4 h, suggesting that the maximum extent of tissue damage (without the involvement of significant edema) was reached within the first 4 h in this model. The enlargement of the lesion after 4 h correlated closely with changes in brain water content.


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