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Does long-term glucose infusion reduce brain damage after transient cerebral ischemia?
Brain Research 912 (2001) 203–205 www.elsevier.com / locate / bres
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Does long-term glucose infusion reduce brain damage after transient cerebral ischemia? Ping An Li*, Qing Ping He, Katalin Csiszar, Bo K. Siesjo¨ Pacific Biomedical Research Center and John A. Burns School of Medicine, University of Hawaii, T312, 1960 East–West Road, Honolulu, HI 96822, USA Accepted 12 June 2001
Abstract A recent study reported that hyperglycemia of a brief duration worsens, and of long duration reduces, ischemic brain damage. To test whether this is a valid conception, we induced 10 min of transient forebrain ischemia, recorded postischemic seizures, and evaluated brain morphology. The results showed that administration of glucose 2 h before ischemia aggravated brain damage, induced seizures, and caused animal death in the same manner as was previously observed when glucose was given 30 min before ischemia. Thus, the conclusion that the influence of glucose on an ischemic transient is dependent upon the duration of hyperglycemia is unsubstantiated. 2001 Elsevier Science B.V. All rights reserved. Theme: Disorders of the nervous system Topic: Ischemia Keywords: Hyperglycemia; Ischemia; Brain damage; Glucose; Seizure; Histopathology
It has been known for decades that preischemic hyperglycemia aggravates ischemic brain damage [4]. This concept has been challenged by Schurr et al. [7], who reported that glucose is beneficial when given 2 h before the induction of ischemia and only harmful when given 15 min before ischemia. They speculated that what aggravates ischemic brain damage is a short-lasting (30–60 min) systemic factor, corticosterone [6]. The results of Schurr et al. [7] were obtained in a global ischemia rat model where ischemia was induced by chest compression; furthermore, the temperature of the animals was allowed to fall to 358C. It has been reported that hypothermia could abolish ischemia-induced glutamate release and reduce brain damage in hyperglycemic animals to the extent observed in hypothermic–normoglycemic rats [2]. Thus hypothermia appears to have a strong effect in reducing hyperglycemiaaggravated ischemic brain damage. It seems justified, therefore, to repeat their experiments with 2 h preischemic hyperglycemia in a rigorously controlled forebrain is*Corresponding author. Tel.: 11-808-956-9575; fax: 11-808-9569481. E-mail address: pingan [email protected] (P.A. Li). ]
chemia model, induced by two-vessel occlusion plus hypotension. Male Wistar rats (Simonsen Laboratory, Gilrey, CA), fasted overnight with free access to tap water, were used. Animal operative procedures are identical to those we have described before [3] and approved by the institutional animal ethic committee. Forebrain ischemia of a 10-min duration was induced as described previously [3]. Two experimental series were performed.
Series I: mortality study Group I: 25% glucose was continuously infused i.v. 2 h before ischemia. Blood glucose concentration, as measured repeatedly, was |20 mmol. N56. Group II: 25% glucose was injected i.p. as a bolus 2 h before ischemia. Blood glucose concentration was |20 mmol. N55. Series II: morphology study Group III: saline was continuously infused i.v. 2 h before ischemia. Blood glucose concentration was 4–6 mmol. N56. Group IV: glucose was continuously infused i.v. 2
0006-8993 / 01 / $ – see front matter 2001 Elsevier Science B.V. All rights reserved. PII: S0006-8993( 01 )02724-X
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P. A. Li et al. / Brain Research 912 (2001) 203 – 205
h before ischemia. Blood glucose concentration was |12 mmol. N511. Brain damage was evaluated after 6 days of recovery. The damage in the striatum, the hippocampal CA1 and CA3 sectors was presented as percent damaged neurons. Damage was counted in one and three microscopic fields at 400 magnification in the cingulate and fronto-parietal cortex, respectively [3]. The average total neuronal count was 450 in the fronto-parietal cortex and 140 in the cingulate cortex. Damage in the thalamus and substantia nigra was graded, where grade 0: no observed damage; grade 1: ,10%, grade 2: 11–50%, and grade 3: .50% damage. Data were analyzed with t-test and Mann–Whitney U-test. Blood glucose concentrations were measured 20 min after glucose injection, 10 min before ischemia and 5 min after recirculation. Blood glucose concentration was |20 mmol in groups I and II, 10–14 mmol in group IV, and 4–6 mmol in group III. PaCO 2 was 35–42 mmHg, PaO 2 , 88–120 mmHg, arterial pH, 7.35–7.45, and blood pressure, 90–130 mmHg in all groups. Postischemic seizures developed in five of six animals in group I after 2–24 h of recirculation and the animals subsequently died of status epilepticus after 20–40 h of recirculation. In group II, 5 / 5 rats developed postischemic seizures after 4–36 h of recirculation and died after 24–36 h of recirculation. None of the rats in group III developed seizures. Four of 11 rats in group IV developed seizures after about 24 h of reperfusion and died between 24 and 72 h of reperfusion. Another seven rats survived for 6 days. Surviving rats from groups III and IV were processed for histopathological evaluation. In the hippocampal CA1 area, normoglycemic ischemia gave 90% and hyperglycemia 75% damage (P.0.05). In the substantia nigra, normoglycemic animals did not show cell damage, while two of seven hyperglycemic rats had grade 2 damage. Normoglycemic ischemia of 10 min duration gave moderate damage in the striatum, and very mild damage in the cingulate cortex and fronto-parietal cortex. The hippocampal CA3 area was virtually spared and only two rats had grade 1 damage in the thalamus. Mild hyperglycemic ischemia exaggerated the damage in the striatum, the CA3 area, the cingulate cortex and fronto-parietal cortex, and the thalamus (Fig. 1). Five animals had infarctions in the fronto-parietal cortex. A set of representative photomicrographs showing the damage in the CA3, the cingulate cortex, and the thalamus is given in Fig. 2. The major specific aim of the present communication is to explore if the concept of that glucose injection 2 h before ischemia is beneficial while glucose injection 15 min before ischemia is harmful is a valid concept in our well established ischemia model. In pursuing this issue we employed glucose i.p. as a bolus injection, or as a continuous i.v. infusion 2 h before ischemia in the first series. In agreement with many literature data reported
Fig. 1. Histopathological outcome after 6 days of recovery in normoglycemic (blood glucose concentration of 4–6 mmol) and mild hyperglycemic (blood glucose concentration of 10–14 mmol) rats subjected to 10 min of forebrain ischemia. Circles denote individuals and bars mean values.
before, glucose-injected rats showed seizure and died within 2 days of recovery, no matter whether the glucose was given as one injection or as a continuous infusion 2 h before ischemia. Our results of the second series also demonstrated that administration of glucose by continuous i.v. infusion 2 h before ischemia aggravates brain damage, and induced seizures in the same manner as was previously observed when glucose was given 30 min before ischemia [3–5,8]. The report by Payne et al. [6] hypothesized that corticosterone is responsible for the hyperglycemia-aggravated damage since glucose injection increased secretion of corticosterone and since corticosterone aggravated ischemic brain damage if it was injected 15 min before ischemia but did not worsen the outcome if it was injected
P. A. Li et al. / Brain Research 912 (2001) 203 – 205
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min in duration) hormone. Thus, it is unlikely hormone is the reason for the detrimental effect of glucose in the current study. In addition, subchronic hyperglycemia of 7 or 28 days duration causes exaggerated brain damage in both transient global or focal ischemia [1,5]. It is very unlikely that 2 days hyperglycemia will lead to vascular change. The present observations clearly suggest that the notion that glucose effect on ischemic brain damage depends on the interval between its injection and ischemia remains unsubstantiated.
Acknowledgements Supported by Hawaii Community Foundation and American Heart Association.
References
Fig. 2. Representative photomicrographs showing the damage in the CA3 (A, B), the cingulate cortex (C, D) and the thalamus (E, F). Normal morphology is observed in normoglycemic animals (B, D, F), while extensive neuronal loss and neutrophil infiltration are evident in hyperglycemic rats (A, C, E) in these three structures. Arrows indicate a few survival neurons in hyperglycemic sections. Magnification: 2003.
2 h before ischemia [6]. It is difficult to use this hypothesis to explain why the rats with glucose injected as a bolus 2 h before ischemia died of seizures and why the rats with glucose continuous infusion 2 h before ischemia showed exaggerated damage. As indicated by these authors that glucose-induced hormone release is a short-lived (30–60
¨ Effects of [1] C. Li, P.-A. Li, Q.-P. He, Y.-B. Ouyang, B.K. Siesjo, streptozotocin-induced hyperglycemia on brain damage following transient ischemia, Neurobiol. Dis. 5 (1998) 117–128. [2] P.-A. Li, Q.P. He, H. Miyashita, W. Howllet, B.K. Siesjo, A. Shuaib, Hypothermia ameliorates ischemic brain damage and suppresses the release of extracellular amino acids in both normo- and hyperglycemic subjects, Exp. Neurol. 158 (1999) 242–253. ¨ Critical [3] P.-A. Li, M. Shamloo, K. Katsura, M.-L. Smith, B.K. Siesjo, values for plasma glucose in aggravating ischemic brain damage: correlation to extracellular pH, Neurobiol. Dis. 2 (1995) 97–108. ¨ Role of hyperglycaemia-related acidosis in [4] P.-A. Li, B.K. Siesjo, ischaemic brain damage, Acta Physiol. Scand. 161 (1997) 567–580. [5] M. Nedergaard, Transient focal ischemia in hyperglycemic rats is associated with increased cerebral infarction, Brain Res. 408 (1987) 79–85. [6] R.S. Payne, A. Schurr, M.T. Tseng, J.J. Miller, B.M. Rigor, Corticosterone: a possible candidate for hyperglycemia-enhanced ischemic neuronal damage, Soc. Neurosci. Abs. 25 (1999) 1845. [7] A. Schurr, R.S. Payne, M.T. Tseng, J.J. Miller, B.M. Rigor, The glucose paradox in cerebral ischemia. New insights, Ann. NY Acad. Sci. 893 (1999) 386–390. ¨ Morphological [8] M.-L. Smith, H. Kalimo, D.S. Warner, B.K. Siesjo, lesions in the brain preceding the development of postischemic seizures, Acta Neuropathol. (Berl.) 76 (1988) 253–264.
Short communication
Does long-term glucose infusion reduce brain damage after transient cerebral ischemia? Ping An Li*, Qing Ping He, Katalin Csiszar, Bo K. Siesjo¨ Pacific Biomedical Research Center and John A. Burns School of Medicine, University of Hawaii, T312, 1960 East–West Road, Honolulu, HI 96822, USA Accepted 12 June 2001
Abstract A recent study reported that hyperglycemia of a brief duration worsens, and of long duration reduces, ischemic brain damage. To test whether this is a valid conception, we induced 10 min of transient forebrain ischemia, recorded postischemic seizures, and evaluated brain morphology. The results showed that administration of glucose 2 h before ischemia aggravated brain damage, induced seizures, and caused animal death in the same manner as was previously observed when glucose was given 30 min before ischemia. Thus, the conclusion that the influence of glucose on an ischemic transient is dependent upon the duration of hyperglycemia is unsubstantiated. 2001 Elsevier Science B.V. All rights reserved. Theme: Disorders of the nervous system Topic: Ischemia Keywords: Hyperglycemia; Ischemia; Brain damage; Glucose; Seizure; Histopathology
It has been known for decades that preischemic hyperglycemia aggravates ischemic brain damage [4]. This concept has been challenged by Schurr et al. [7], who reported that glucose is beneficial when given 2 h before the induction of ischemia and only harmful when given 15 min before ischemia. They speculated that what aggravates ischemic brain damage is a short-lasting (30–60 min) systemic factor, corticosterone [6]. The results of Schurr et al. [7] were obtained in a global ischemia rat model where ischemia was induced by chest compression; furthermore, the temperature of the animals was allowed to fall to 358C. It has been reported that hypothermia could abolish ischemia-induced glutamate release and reduce brain damage in hyperglycemic animals to the extent observed in hypothermic–normoglycemic rats [2]. Thus hypothermia appears to have a strong effect in reducing hyperglycemiaaggravated ischemic brain damage. It seems justified, therefore, to repeat their experiments with 2 h preischemic hyperglycemia in a rigorously controlled forebrain is*Corresponding author. Tel.: 11-808-956-9575; fax: 11-808-9569481. E-mail address: pingan [email protected] (P.A. Li). ]
chemia model, induced by two-vessel occlusion plus hypotension. Male Wistar rats (Simonsen Laboratory, Gilrey, CA), fasted overnight with free access to tap water, were used. Animal operative procedures are identical to those we have described before [3] and approved by the institutional animal ethic committee. Forebrain ischemia of a 10-min duration was induced as described previously [3]. Two experimental series were performed.
Series I: mortality study Group I: 25% glucose was continuously infused i.v. 2 h before ischemia. Blood glucose concentration, as measured repeatedly, was |20 mmol. N56. Group II: 25% glucose was injected i.p. as a bolus 2 h before ischemia. Blood glucose concentration was |20 mmol. N55. Series II: morphology study Group III: saline was continuously infused i.v. 2 h before ischemia. Blood glucose concentration was 4–6 mmol. N56. Group IV: glucose was continuously infused i.v. 2
0006-8993 / 01 / $ – see front matter 2001 Elsevier Science B.V. All rights reserved. PII: S0006-8993( 01 )02724-X
204
P. A. Li et al. / Brain Research 912 (2001) 203 – 205
h before ischemia. Blood glucose concentration was |12 mmol. N511. Brain damage was evaluated after 6 days of recovery. The damage in the striatum, the hippocampal CA1 and CA3 sectors was presented as percent damaged neurons. Damage was counted in one and three microscopic fields at 400 magnification in the cingulate and fronto-parietal cortex, respectively [3]. The average total neuronal count was 450 in the fronto-parietal cortex and 140 in the cingulate cortex. Damage in the thalamus and substantia nigra was graded, where grade 0: no observed damage; grade 1: ,10%, grade 2: 11–50%, and grade 3: .50% damage. Data were analyzed with t-test and Mann–Whitney U-test. Blood glucose concentrations were measured 20 min after glucose injection, 10 min before ischemia and 5 min after recirculation. Blood glucose concentration was |20 mmol in groups I and II, 10–14 mmol in group IV, and 4–6 mmol in group III. PaCO 2 was 35–42 mmHg, PaO 2 , 88–120 mmHg, arterial pH, 7.35–7.45, and blood pressure, 90–130 mmHg in all groups. Postischemic seizures developed in five of six animals in group I after 2–24 h of recirculation and the animals subsequently died of status epilepticus after 20–40 h of recirculation. In group II, 5 / 5 rats developed postischemic seizures after 4–36 h of recirculation and died after 24–36 h of recirculation. None of the rats in group III developed seizures. Four of 11 rats in group IV developed seizures after about 24 h of reperfusion and died between 24 and 72 h of reperfusion. Another seven rats survived for 6 days. Surviving rats from groups III and IV were processed for histopathological evaluation. In the hippocampal CA1 area, normoglycemic ischemia gave 90% and hyperglycemia 75% damage (P.0.05). In the substantia nigra, normoglycemic animals did not show cell damage, while two of seven hyperglycemic rats had grade 2 damage. Normoglycemic ischemia of 10 min duration gave moderate damage in the striatum, and very mild damage in the cingulate cortex and fronto-parietal cortex. The hippocampal CA3 area was virtually spared and only two rats had grade 1 damage in the thalamus. Mild hyperglycemic ischemia exaggerated the damage in the striatum, the CA3 area, the cingulate cortex and fronto-parietal cortex, and the thalamus (Fig. 1). Five animals had infarctions in the fronto-parietal cortex. A set of representative photomicrographs showing the damage in the CA3, the cingulate cortex, and the thalamus is given in Fig. 2. The major specific aim of the present communication is to explore if the concept of that glucose injection 2 h before ischemia is beneficial while glucose injection 15 min before ischemia is harmful is a valid concept in our well established ischemia model. In pursuing this issue we employed glucose i.p. as a bolus injection, or as a continuous i.v. infusion 2 h before ischemia in the first series. In agreement with many literature data reported
Fig. 1. Histopathological outcome after 6 days of recovery in normoglycemic (blood glucose concentration of 4–6 mmol) and mild hyperglycemic (blood glucose concentration of 10–14 mmol) rats subjected to 10 min of forebrain ischemia. Circles denote individuals and bars mean values.
before, glucose-injected rats showed seizure and died within 2 days of recovery, no matter whether the glucose was given as one injection or as a continuous infusion 2 h before ischemia. Our results of the second series also demonstrated that administration of glucose by continuous i.v. infusion 2 h before ischemia aggravates brain damage, and induced seizures in the same manner as was previously observed when glucose was given 30 min before ischemia [3–5,8]. The report by Payne et al. [6] hypothesized that corticosterone is responsible for the hyperglycemia-aggravated damage since glucose injection increased secretion of corticosterone and since corticosterone aggravated ischemic brain damage if it was injected 15 min before ischemia but did not worsen the outcome if it was injected
P. A. Li et al. / Brain Research 912 (2001) 203 – 205
205
min in duration) hormone. Thus, it is unlikely hormone is the reason for the detrimental effect of glucose in the current study. In addition, subchronic hyperglycemia of 7 or 28 days duration causes exaggerated brain damage in both transient global or focal ischemia [1,5]. It is very unlikely that 2 days hyperglycemia will lead to vascular change. The present observations clearly suggest that the notion that glucose effect on ischemic brain damage depends on the interval between its injection and ischemia remains unsubstantiated.
Acknowledgements Supported by Hawaii Community Foundation and American Heart Association.
References
Fig. 2. Representative photomicrographs showing the damage in the CA3 (A, B), the cingulate cortex (C, D) and the thalamus (E, F). Normal morphology is observed in normoglycemic animals (B, D, F), while extensive neuronal loss and neutrophil infiltration are evident in hyperglycemic rats (A, C, E) in these three structures. Arrows indicate a few survival neurons in hyperglycemic sections. Magnification: 2003.
2 h before ischemia [6]. It is difficult to use this hypothesis to explain why the rats with glucose injected as a bolus 2 h before ischemia died of seizures and why the rats with glucose continuous infusion 2 h before ischemia showed exaggerated damage. As indicated by these authors that glucose-induced hormone release is a short-lived (30–60
¨ Effects of [1] C. Li, P.-A. Li, Q.-P. He, Y.-B. Ouyang, B.K. Siesjo, streptozotocin-induced hyperglycemia on brain damage following transient ischemia, Neurobiol. Dis. 5 (1998) 117–128. [2] P.-A. Li, Q.P. He, H. Miyashita, W. Howllet, B.K. Siesjo, A. Shuaib, Hypothermia ameliorates ischemic brain damage and suppresses the release of extracellular amino acids in both normo- and hyperglycemic subjects, Exp. Neurol. 158 (1999) 242–253. ¨ Critical [3] P.-A. Li, M. Shamloo, K. Katsura, M.-L. Smith, B.K. Siesjo, values for plasma glucose in aggravating ischemic brain damage: correlation to extracellular pH, Neurobiol. Dis. 2 (1995) 97–108. ¨ Role of hyperglycaemia-related acidosis in [4] P.-A. Li, B.K. Siesjo, ischaemic brain damage, Acta Physiol. Scand. 161 (1997) 567–580. [5] M. Nedergaard, Transient focal ischemia in hyperglycemic rats is associated with increased cerebral infarction, Brain Res. 408 (1987) 79–85. [6] R.S. Payne, A. Schurr, M.T. Tseng, J.J. Miller, B.M. Rigor, Corticosterone: a possible candidate for hyperglycemia-enhanced ischemic neuronal damage, Soc. Neurosci. Abs. 25 (1999) 1845. [7] A. Schurr, R.S. Payne, M.T. Tseng, J.J. Miller, B.M. Rigor, The glucose paradox in cerebral ischemia. New insights, Ann. NY Acad. Sci. 893 (1999) 386–390. ¨ Morphological [8] M.-L. Smith, H. Kalimo, D.S. Warner, B.K. Siesjo, lesions in the brain preceding the development of postischemic seizures, Acta Neuropathol. (Berl.) 76 (1988) 253–264.