Limits...
Excess salt increases infarct size produced by photothrombotic distal middle cerebral artery occlusion in spontaneously hypertensive rats.

Yao H, Nabika T - PLoS ONE (2014)

Bottom Line: Salt loading did not affect blood pressure levels in SHR and WKY.After MCAO, regional cerebral blood flow (CBF), determined with two ways of laser-Doppler flowmetry (one-point measurement or manual scanning), was more steeply decreased in the salt-loaded group than in the control group.These results show the detrimental effects of salt loading on intra-ischemic CBF and subsequent brain infarction produced by phototrhombotic MCAO in hypertensive rats.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Neurochemistry, National Hospital Organization Hizen Psychiatric Center, Saga, Japan.

ABSTRACT
Cerebral circulation is known to be vulnerable to high salt loading. However, no study has investigated the effects of excess salt on focal ischemic brain injury. After 14 days of salt loading (0.9% saline) or water, spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) were subjected to photothrombotic middle cerebral artery occlusion (MCAO), and infarct volume was determined at 48 h after MCAO: albumin and hemoglobin contents in discrete brain regions were also determined in SHR. Salt loading did not affect blood pressure levels in SHR and WKY. After MCAO, regional cerebral blood flow (CBF), determined with two ways of laser-Doppler flowmetry (one-point measurement or manual scanning), was more steeply decreased in the salt-loaded group than in the control group. In SHR/Izm, infarct volume in the salt-loaded group was 112±27 mm3, which was significantly larger than 77±12 mm3 in the control group (p = 0.002), while the extents of blood-brain barrier disruption (brain albumin and hemoglobin levels) were not affected by excess salt. In WKY, salt loading did not significantly increase infarct size. These results show the detrimental effects of salt loading on intra-ischemic CBF and subsequent brain infarction produced by phototrhombotic MCAO in hypertensive rats.

Show MeSH

Related in: MedlinePlus

Schematic representation of cerebral blood flow (CBF) measurements and photothrombotic distal middle cerebral artery occlusion (MCAO).The laser-Doppler probe was positioned at 2 mm posterior and 4 mm lateral to the bregma (X) (A). In a subgroup of rats, regional CBF was measured at points 2 mm posterior and 2.0 to 3.0 mm lateral to the bregma by scanning the probe at 0.1 mm intervals (A). In case that it is difficult to place the “scanning” probe avoiding superficial veins and arterioles, the CBF value was substituted by the average of arbitrary units determined on neighboring two appropriate points. The lower portion of the exposed distal MCA was irradiated for 2 min with an infusion of photosensitizing dye rose bengal, and then the laser beam was moved to an additional site just proximal to the first irradiated site for 2 min (two-point hit) (A). CBF was determined at 2 mm posterior and 4 mm lateral to the bregma (B). After distal MCA occlusion, CBF was more markedly decreased in the salt-loaded group compared with the control group (n = 5–6). By means of scanning of the laser-Doppler probe, CBF was determined at 2 mm posterior and 2.0 mm to 3.0 mm lateral to the bregma (n = 3–4) (C). Values are expressed as mean±S.D. *p<0.05 vs. salt (−).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4016244&req=5

pone-0097109-g001: Schematic representation of cerebral blood flow (CBF) measurements and photothrombotic distal middle cerebral artery occlusion (MCAO).The laser-Doppler probe was positioned at 2 mm posterior and 4 mm lateral to the bregma (X) (A). In a subgroup of rats, regional CBF was measured at points 2 mm posterior and 2.0 to 3.0 mm lateral to the bregma by scanning the probe at 0.1 mm intervals (A). In case that it is difficult to place the “scanning” probe avoiding superficial veins and arterioles, the CBF value was substituted by the average of arbitrary units determined on neighboring two appropriate points. The lower portion of the exposed distal MCA was irradiated for 2 min with an infusion of photosensitizing dye rose bengal, and then the laser beam was moved to an additional site just proximal to the first irradiated site for 2 min (two-point hit) (A). CBF was determined at 2 mm posterior and 4 mm lateral to the bregma (B). After distal MCA occlusion, CBF was more markedly decreased in the salt-loaded group compared with the control group (n = 5–6). By means of scanning of the laser-Doppler probe, CBF was determined at 2 mm posterior and 2.0 mm to 3.0 mm lateral to the bregma (n = 3–4) (C). Values are expressed as mean±S.D. *p<0.05 vs. salt (−).

Mentions: By means of photothrombosis [12], distal MCA was occluded as previously described [10], [11]. Briefly, a krypton laser operating at 568 nm (643R-Y-A01, Melles Griot Inc.) was used to irradiate the distal MCA at a power of 20 mW (an average intensity of 15.9 W/cm2) for 4 min (Figure 1A). The laser beam was focused with a 30-cm-f.l. convex lens (KPX 112, Newport Corporation, Irvine, CA, USA) and positioned onto the distal MCA after reflection from a mirror. The photosensitizing dye rose bengal (15 mg/mL in 0.9% saline; Wako Pure Chemical Industries Ltd, Osaka, Japan) was administered intravenously to a body dose of 20 mg/kg over 90 sec starting simultaneously with 4 min of laser irradiation.


Excess salt increases infarct size produced by photothrombotic distal middle cerebral artery occlusion in spontaneously hypertensive rats.

Yao H, Nabika T - PLoS ONE (2014)

Schematic representation of cerebral blood flow (CBF) measurements and photothrombotic distal middle cerebral artery occlusion (MCAO).The laser-Doppler probe was positioned at 2 mm posterior and 4 mm lateral to the bregma (X) (A). In a subgroup of rats, regional CBF was measured at points 2 mm posterior and 2.0 to 3.0 mm lateral to the bregma by scanning the probe at 0.1 mm intervals (A). In case that it is difficult to place the “scanning” probe avoiding superficial veins and arterioles, the CBF value was substituted by the average of arbitrary units determined on neighboring two appropriate points. The lower portion of the exposed distal MCA was irradiated for 2 min with an infusion of photosensitizing dye rose bengal, and then the laser beam was moved to an additional site just proximal to the first irradiated site for 2 min (two-point hit) (A). CBF was determined at 2 mm posterior and 4 mm lateral to the bregma (B). After distal MCA occlusion, CBF was more markedly decreased in the salt-loaded group compared with the control group (n = 5–6). By means of scanning of the laser-Doppler probe, CBF was determined at 2 mm posterior and 2.0 mm to 3.0 mm lateral to the bregma (n = 3–4) (C). Values are expressed as mean±S.D. *p<0.05 vs. salt (−).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016244&req=5

pone-0097109-g001: Schematic representation of cerebral blood flow (CBF) measurements and photothrombotic distal middle cerebral artery occlusion (MCAO).The laser-Doppler probe was positioned at 2 mm posterior and 4 mm lateral to the bregma (X) (A). In a subgroup of rats, regional CBF was measured at points 2 mm posterior and 2.0 to 3.0 mm lateral to the bregma by scanning the probe at 0.1 mm intervals (A). In case that it is difficult to place the “scanning” probe avoiding superficial veins and arterioles, the CBF value was substituted by the average of arbitrary units determined on neighboring two appropriate points. The lower portion of the exposed distal MCA was irradiated for 2 min with an infusion of photosensitizing dye rose bengal, and then the laser beam was moved to an additional site just proximal to the first irradiated site for 2 min (two-point hit) (A). CBF was determined at 2 mm posterior and 4 mm lateral to the bregma (B). After distal MCA occlusion, CBF was more markedly decreased in the salt-loaded group compared with the control group (n = 5–6). By means of scanning of the laser-Doppler probe, CBF was determined at 2 mm posterior and 2.0 mm to 3.0 mm lateral to the bregma (n = 3–4) (C). Values are expressed as mean±S.D. *p<0.05 vs. salt (−).
Mentions: By means of photothrombosis [12], distal MCA was occluded as previously described [10], [11]. Briefly, a krypton laser operating at 568 nm (643R-Y-A01, Melles Griot Inc.) was used to irradiate the distal MCA at a power of 20 mW (an average intensity of 15.9 W/cm2) for 4 min (Figure 1A). The laser beam was focused with a 30-cm-f.l. convex lens (KPX 112, Newport Corporation, Irvine, CA, USA) and positioned onto the distal MCA after reflection from a mirror. The photosensitizing dye rose bengal (15 mg/mL in 0.9% saline; Wako Pure Chemical Industries Ltd, Osaka, Japan) was administered intravenously to a body dose of 20 mg/kg over 90 sec starting simultaneously with 4 min of laser irradiation.

Bottom Line: Salt loading did not affect blood pressure levels in SHR and WKY.After MCAO, regional cerebral blood flow (CBF), determined with two ways of laser-Doppler flowmetry (one-point measurement or manual scanning), was more steeply decreased in the salt-loaded group than in the control group.These results show the detrimental effects of salt loading on intra-ischemic CBF and subsequent brain infarction produced by phototrhombotic MCAO in hypertensive rats.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Neurochemistry, National Hospital Organization Hizen Psychiatric Center, Saga, Japan.

ABSTRACT
Cerebral circulation is known to be vulnerable to high salt loading. However, no study has investigated the effects of excess salt on focal ischemic brain injury. After 14 days of salt loading (0.9% saline) or water, spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) were subjected to photothrombotic middle cerebral artery occlusion (MCAO), and infarct volume was determined at 48 h after MCAO: albumin and hemoglobin contents in discrete brain regions were also determined in SHR. Salt loading did not affect blood pressure levels in SHR and WKY. After MCAO, regional cerebral blood flow (CBF), determined with two ways of laser-Doppler flowmetry (one-point measurement or manual scanning), was more steeply decreased in the salt-loaded group than in the control group. In SHR/Izm, infarct volume in the salt-loaded group was 112±27 mm3, which was significantly larger than 77±12 mm3 in the control group (p = 0.002), while the extents of blood-brain barrier disruption (brain albumin and hemoglobin levels) were not affected by excess salt. In WKY, salt loading did not significantly increase infarct size. These results show the detrimental effects of salt loading on intra-ischemic CBF and subsequent brain infarction produced by phototrhombotic MCAO in hypertensive rats.

Show MeSH
Related in: MedlinePlus