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Lipopolysaccharide-induced blood-brain barrier disruption: roles of cyclooxygenase, oxidative stress, neuroinflammation, and elements of the neurovascular unit.

Banks WA, Gray AM, Erickson MA, Salameh TS, Damodarasamy M, Sheibani N, Meabon JS, Wing EE, Morofuji Y, Cook DG, Reed MJ - J Neuroinflammation (2015)

Bottom Line: N-acetylcysteine did not affect disruption.In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

View Article: PubMed Central - PubMed

Affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. wabanks1@uw.edu.

ABSTRACT

Background: Disruption of the blood-brain barrier (BBB) occurs in many diseases and is often mediated by inflammatory and neuroimmune mechanisms. Inflammation is well established as a cause of BBB disruption, but many mechanistic questions remain.

Methods: We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in mice. BBB disruption was measured using (14)C-sucrose and radioactively labeled albumin. Brain cytokine responses were measured using multiplex technology and dependence on cyclooxygenase (COX) and oxidative stress determined by treatments with indomethacin and N-acetylcysteine. Astrocyte and microglia/macrophage responses were measured using brain immunohistochemistry. In vitro studies used Transwell cultures of primary brain endothelial cells co- or tri-cultured with astrocytes and pericytes to measure effects of LPS on transendothelial electrical resistance (TEER), cellular distribution of tight junction proteins, and permeability to (14)C-sucrose and radioactive albumin.

Results: In comparison to LPS-induced weight loss, the BBB was relatively resistant to LPS-induced disruption. Disruption occurred only with the highest dose of LPS and was most evident in the frontal cortex, thalamus, pons-medulla, and cerebellum with no disruption in the hypothalamus. The in vitro and in vivo patterns of LPS-induced disruption as measured with (14)C-sucrose, radioactive albumin, and TEER suggested involvement of both paracellular and transcytotic pathways. Disruption as measured with albumin and (14)C-sucrose, but not TEER, was blocked by indomethacin. N-acetylcysteine did not affect disruption. In vivo, the measures of neuroinflammation induced by LPS were mainly not reversed by indomethacin. In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.

Conclusions: The BBB is relatively resistant to LPS-induced disruption with some brain regions more vulnerable than others. LPS-induced disruption appears is to be dependent on COX but not on oxidative stress. Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

No MeSH data available.


Related in: MedlinePlus

Effects of indomethacin and N-acetylcysteine on LPS-induced BBB disruption. Panel a shows that pre-treatment with indomethacin prevented LPS-induced BBB disruption (n = 7–8/group), whereas panel b shows that N-acetylcysteine was without effect (9–10/group). *p < 0.05; **p < 0.01; ****p < 0.001
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Fig3: Effects of indomethacin and N-acetylcysteine on LPS-induced BBB disruption. Panel a shows that pre-treatment with indomethacin prevented LPS-induced BBB disruption (n = 7–8/group), whereas panel b shows that N-acetylcysteine was without effect (9–10/group). *p < 0.05; **p < 0.01; ****p < 0.001

Mentions: To determine whether the increased BBB permeability induced by LPS could be blocked by the administration of the antioxidant NAC or the COX inhibitor indomethacin, we administered these agents intraperitoneally 30 min prior to the injections of LPS. For these studies, the three-injection regimen was used so as to match previously published BBB studies [6, 7, 38, 39]. As shown in Fig. 3, indomethacin (panel A), but not NAC (panel B), inhibited the LPS-induced increase in BBB permeability to 14C-sucrose. Indomethacin also prevented the LPS-induced decrease in body weight (data not shown) as has been previously reported [6]. Neither LPS nor indomethacin has an effect on ZO-1 protein levels as measured by Western blotting (data not shown).Fig. 3


Lipopolysaccharide-induced blood-brain barrier disruption: roles of cyclooxygenase, oxidative stress, neuroinflammation, and elements of the neurovascular unit.

Banks WA, Gray AM, Erickson MA, Salameh TS, Damodarasamy M, Sheibani N, Meabon JS, Wing EE, Morofuji Y, Cook DG, Reed MJ - J Neuroinflammation (2015)

Effects of indomethacin and N-acetylcysteine on LPS-induced BBB disruption. Panel a shows that pre-treatment with indomethacin prevented LPS-induced BBB disruption (n = 7–8/group), whereas panel b shows that N-acetylcysteine was without effect (9–10/group). *p < 0.05; **p < 0.01; ****p < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4660627&req=5

Fig3: Effects of indomethacin and N-acetylcysteine on LPS-induced BBB disruption. Panel a shows that pre-treatment with indomethacin prevented LPS-induced BBB disruption (n = 7–8/group), whereas panel b shows that N-acetylcysteine was without effect (9–10/group). *p < 0.05; **p < 0.01; ****p < 0.001
Mentions: To determine whether the increased BBB permeability induced by LPS could be blocked by the administration of the antioxidant NAC or the COX inhibitor indomethacin, we administered these agents intraperitoneally 30 min prior to the injections of LPS. For these studies, the three-injection regimen was used so as to match previously published BBB studies [6, 7, 38, 39]. As shown in Fig. 3, indomethacin (panel A), but not NAC (panel B), inhibited the LPS-induced increase in BBB permeability to 14C-sucrose. Indomethacin also prevented the LPS-induced decrease in body weight (data not shown) as has been previously reported [6]. Neither LPS nor indomethacin has an effect on ZO-1 protein levels as measured by Western blotting (data not shown).Fig. 3

Bottom Line: N-acetylcysteine did not affect disruption.In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

View Article: PubMed Central - PubMed

Affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. wabanks1@uw.edu.

ABSTRACT

Background: Disruption of the blood-brain barrier (BBB) occurs in many diseases and is often mediated by inflammatory and neuroimmune mechanisms. Inflammation is well established as a cause of BBB disruption, but many mechanistic questions remain.

Methods: We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in mice. BBB disruption was measured using (14)C-sucrose and radioactively labeled albumin. Brain cytokine responses were measured using multiplex technology and dependence on cyclooxygenase (COX) and oxidative stress determined by treatments with indomethacin and N-acetylcysteine. Astrocyte and microglia/macrophage responses were measured using brain immunohistochemistry. In vitro studies used Transwell cultures of primary brain endothelial cells co- or tri-cultured with astrocytes and pericytes to measure effects of LPS on transendothelial electrical resistance (TEER), cellular distribution of tight junction proteins, and permeability to (14)C-sucrose and radioactive albumin.

Results: In comparison to LPS-induced weight loss, the BBB was relatively resistant to LPS-induced disruption. Disruption occurred only with the highest dose of LPS and was most evident in the frontal cortex, thalamus, pons-medulla, and cerebellum with no disruption in the hypothalamus. The in vitro and in vivo patterns of LPS-induced disruption as measured with (14)C-sucrose, radioactive albumin, and TEER suggested involvement of both paracellular and transcytotic pathways. Disruption as measured with albumin and (14)C-sucrose, but not TEER, was blocked by indomethacin. N-acetylcysteine did not affect disruption. In vivo, the measures of neuroinflammation induced by LPS were mainly not reversed by indomethacin. In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.

Conclusions: The BBB is relatively resistant to LPS-induced disruption with some brain regions more vulnerable than others. LPS-induced disruption appears is to be dependent on COX but not on oxidative stress. Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

No MeSH data available.


Related in: MedlinePlus