Preventive effects of antenatal CDP-choline in a rat model of neonatal hyperoxia-induced lung injury

Antenatal steroid administration to pregnant women at risk of prematurity provides pulmonary maturation in infants, while it has limited effects on incidence of bronchopulmonary dysplasia (BPD), the clinical expression of hyperoxia-induced lung injury (HILI). Cytidine-5'-diphosphate choline (CDP-choline) was shown to alleviate HILI when administered to newborn rats. Therefore, we investigated effects of maternal administration of CDP-choline, alone or in combination with betamethasone, on lung maturation in neonatal rats subjected to HILI immediately after birth. Pregnant rats were randomly assigned to one of the four treatments: saline (1 mL/kg), CDP-choline (300 mg/kg), betamethasone (0.4 mg/kg), or CDP-choline plus betamethasone (combination therapy). From postnatal day 1 to 11, pups born to mothers in the same treatment group were pooled and randomly assigned to either normoxia or hyperoxia group. Biochemical an d histopathological effects of CDP-choline on neonatal lung tissue were evaluated. Antenatal CDP-choline treatment increased levels of phosphatidylcholine and total lung phospholipids, decreased apoptosis, and improved alveolarization. The outcomes were further improved with combination therapy compared to the administration of CDP-choline or betamethasone alone. These results demonstrate that antenatal CDP-choline treatment provides benefit in experimental HILI either alone or more intensively when administered along with a steroid, suggesting a possible utility for CDP-choline against BPD.

Neuroprotective effects of uridine in a rat model of neonatal hypoxic-ischemic encephalopathy

Neonatal hypoxic-ischemic encephalopathy (HIE) is a major cause of neurological disability requiring newer therapeutic strategies. Uridine is the principal circulating pyrimidine in humans and a substrate for nucleotides and membrane phospholipids. The objective of this study was to investigate the effects of uridine in a neonatal rat model of HIE. Rat pups subjected to hypoxic-ischemic insult on postnatal day 7 were injected intraperitoneally with either saline or uridine (100, 300 or 500mg/kg) for three consecutive days and brains were collected for evaluation of brain infarct volume and apoptosis. Compared with Control group, uridine at 300 and 500mg/kg doses significantly reduced percent infarct volume, TUNEL(+) cell ratio and active Caspase-3 immunoreactivity in the cortex, as well as in CA1 and CA3 regions of the hippocampus. Uridine (300 and 500mg/kg) also decreased active Caspase-3 expression in the ipsilateral hemisphere. These data indicate that uridine dose-dependently reduces brain injury in a rat model of neonatal HIE by decreasing apoptosis.

Neuroprotective effects of melatonin administered alone or in combination with topiramate in neonatal hypoxic-ischemic rat model

PURPOSE

The objective of this study was to compare the effects of two neuroprotective agents; melatonin, a free radical scavenger and topiramate, AMPA/kainate receptor antagonist, administered alone or in combination in neonatal hypoxic-ischemic model.

METHODS

After being anesthetized, 7-day-old pups underwent ischemia followed by exposure to hypoxia. The pups were divided into 4 groups in order to receive the vehicle, melatonin, topiramate and combination of topiramate and melatonin. These were administered intraperitoneally for three times; the first before ischemia, the second after hypoxia and the third 24 hours after the second dose. After sacrification, infarct volume and apoptosis were evaluated.

RESULTS

Percent infarcted brain volume was significantly reduced in rats which received drugs compared with those which received the vehicle. The number of TUNEL positive cells per unit area in hippocampus and cortex were markedly reduced in drug treated groups compared with control group. No significant differences were found regarding percent infarcted brain volume and number of TUNEL positive cells among drug-treated groups.

CONCLUSIONS

Melatonin and topiramate, administered either alone or in combination significantly reduced the percent infarcted brain volume and number of TUNEL positive cells suggesting that these agents may confer benefit in treatment of infants with hypoxic-ischemic encephalopathy.

Citicoline and postconditioning provides neuroprotection in a rat model of ischemic spinal cord injury

BACKGROUND

Ischemic spinal cord injury is a chain of events caused by the reduction and/or cessation of spinal cord blood flow, which results in neuronal degeneration and loss. Ischemic postconditioning is defined as a series of intermittent interruptions of blood flow in the early phase of reperfusion and has been shown to reduce the infarct size in cerebral ischemia. Our study aimed to characterize the relationship between the neuronal injury-decreasing effects of citicoline and ischemic postconditioning, which were proven to be effective against the apoptotic process.

METHOD

Spinal cord ischemia was produced in rats using an intrathoracic approach to implement the synchronous arcus aorta and subclavian artery clipping method. In our study, 42 male Sprague-Dawley rats (309 +/- 27 g) were used. Animals were divided into sham operated, spinal ischemia, citicoline, postconditioning, and postconditioning citicoline groups. Postconditioning was generated by six cycles of 1 min occlusion/5 min reperfusion. A 600 mmol/kg dose of citicoline was given intraperitoneally before ischemia in the citicoline and postconditioning citicoline groups. All rats were sacrificed 96 h after reperfusion. For immunohistochemical analysis, bcl-2, caspase 3, caspase 9, and bax immune staining were performed. Caspase 3, caspase 9, bax, and bcl-2 were used as apoptotic and antiapoptotic markers, respectively.

FINDINGS

The blood pressure values obtained at the onset of reperfusion were significantly lower than the preischemic values. A difference in immunohistochemical scoring was detected between the caspase 3, caspase 9, bax, and bcl-2 groups. When comparisons between the ischemia (groups 2, 3, 4, and 5) and sham groups (group 1) were performed, a significant increase in caspase 3, caspase 9, bax, and bcl-2 was detected. When comparing the subgroups, the average score of caspase 9 was found to be significantly higher in ischemia group 2. The average score of bcl-2 was also found to be significantly higher in postconditioning and citicoline group 5.

CONCLUSIONS

It is thus thought that combining citicoline with postconditioning provides protection by inhibiting the caspase pathway and by increasing the antiapoptotic proteins.

Neuroprotective effects of postconditioning on lipid peroxidation and apoptosis after focal cerebral ischemia/reperfusion injury in rats

AIM

Apoptosis after cerebral ischemia/reperfusion (I/R) injury leads to the process of cell death. The deal therapeutic approach would target the apoptosis after I/R. Ischemic postconditioning is a recently discovered neuroprotective strategy that involves the application of brief mechanical reperfusion with a specific algorithm at the onset of reperfusion following an ischemic period.

MATERIAL AND METHODS

Transient MCAo was performed on male SD (275+/-25 g) rats with intraluminal thread insertion for 2 hrs. Rats (n:36) were treated with postconditioning after 60 minutes of occlusion. The postconditioning algorithm was 30 secs of brief reperfusion followed by 30 secs of MCAo and this cycle was repeated 3 times at the onset of reperfusion.

RESULTS

After I/R injury, % change of the malonyldialdehyde (MDA) levels in the cortex, which is an index of lipid peroxidation, was found significantly higher in the I/R group. On the other hand postconditioning upregulated Bcl-2 and Bax translocation to the mitochondria, and caspase-3 activity and also reduced oxidative stress levels.

CONCLUSION

These findings indicated this neuroprotective effect is most likely achieved by antiapoptotic mechanisms through caspase pathways.

Effects of citicoline used alone and in combination with mild hypothermia on apoptosis induced by focal cerebral ischemia in rats

The effects of citicoline used either alone or in combination with hypothermia on the suppression of apoptotic processes after transient focal cerebral ischemia were investigated. Middle cerebral artery occlusion (MCAo) was performed for 2 hours on Sprague-Dawley (SD) rats using intraluminal thread insertion. The treatment groups were as follows: Group 1, sham-operated; Group 2, saline; Group 3, citicoline (400mg/kg intraperitoneal.); Group 4, hypothermia (34+/-1 degrees C); Group 5, citicoline+hypothermia. All rats were reperfused for 24 hours, and after sacrifice and transcardiac perfusion, immunohistochemical studies were performed for markers of apoptosis. In Group 2, the Bcl-2 immunostaining score (mean+/-standard deviation, 0.71+/-0.75) was lower compared to Groups 3, 4 and 5 (2.33+/-0.81; 3.00+/-0.00; 2.20+/-0.83; p<0.05). There was higher expression of caspase-3 proteins in Group 2 (2.28+/-0.95) compared to Group 5 (1.50+/-0.83; p<0.05). Bax proteins were also increased in Group 2 (1.85+/-1.06) compared to Group 5 (0.40+/-0.54) and in Group 4 (2.00+/-0.00) compared to Group 5 (0.40+/-0.54; p<0.05). Significant differences in caspase-9 immunostaining scores were found in Group 2 (2.29+/-0.96) compared to Group 5 (0.20+/-0.44) (p<0.05); Group 3 (1.00+/-0.70) compared to Group 5 (0.20+/-0.44; p<0.05); and Group 4 (3.00+/-0.00; p<0.05) compared to Group 5 (0.40+/-0.54; p<0.05). Thus by suppressing apoptotic processes citicoline with hypothermia is more effective than either used alone in ameliorating cerebral damage after transient focal ischemia.

Neuroproctective effects of ischemic tolerance (preconditioning) and postconditioning

Elucidation of the endogenous cell survival pathways involved in ischemic tolerance (preconditioning) and postconditioning has significant clinical implications for preventing neuronal damage in susceptible patients. Ischemic tolerance is a phenomenon in which the brain protects itself against future injury by adapting to low doses of noxious insults. Ischemic postconditioning is defined as brief periods of reperfusion alternating with re-occlusion applied during the very early minutes of reperfusion that mechanically alters the hydrodynamics of reperfusion. Similar pathways and molecules play a role in pre-and postconditioning but their roles and timing are different in each conditioning. Understanding the neuroprotective effects of mechanisms underlying conditioning has been elusive, but NMDA receptor activation, nitric oxide, inflammatory cytokines, and suppression of the innate immune system appear to have a role. Reactive oxygen species and classical ligand stimuli play a role in postconditioning with KATP channels and protein kinase C pathways acting as mediators.

Atrial natriuretic peptide: could it be a marker for postoperative recurrent effusions after Fontan circulation in complex congenital heart defects?

Fontan operation and its modifications are used for the physiological correction of complex congenital heart malformations with functionally single ventricle. Atrial natriuretic peptide (ANP), a physiological diuretic and vasodilator that--together with the effects of cardiopulmonary bypass--plays an important role in the augmentation of capillary permeability in Fontan patients. The rise in right atrial pressure and wall stress is an important stimulus for the release of ANP. ANP levels were measured before and early after surgery in Fontan group (n = 20) and control group (n = 20, patients with simple cardiac defects) to study its influence on and association with mean right atrial pressure, pulmonary vascular resistance (PVR), systemic vascular resistance, amount of drainage during early and late postoperative period, duration of intensive care unit and hospital stay, and need for colloid supplement. Early postoperative ANP values showed a negative correlation with PVR (r = -0.55) and total drainage (r = -0.88). There was no significant change in ANP during surgery or in the postoperative period in control patients. Reduction of PVR and maintenance of efficient urine output are important in the management of Fontan circulation. We conclude that high levels of ANP measured early after Fontan operation can be used as a marker for the successful establishment of Fontan circulation in patients with complex congenital heart defects.

Effects of intranigral vs intrastriatal fetal mesencephalic neural grafts on motor behavior disorders in a rat Parkinson model

BACKGROUND

Numerous experimental and clinical studies have shown that intrastriatal fetal mesencephalic grafts grow, survive, and reinnervate host brain tissue, resulting in partial recovery of motor deficits. In addition, pharmacological evidence indicates that these grafts increase dopamine secretion in lesioned brain. However, to date, no grafting method has completely restored the nigrostriatal pathway, and there is no consensus on optimal graft numbers or locations. This study compared outcomes with multiple striatal grafts vs a single intranigral graft in a rat model of Parkinson disease.

METHODS

Forty-one female Wistar rats weighing 200 to 250 g were used. First, baseline rotational behavior testing with amphetamine injection was done to identify each animal's dominant nigrostriatal pathway (left vs right hemisphere). Some rats then received a unilateral intranigral injection of 6-hydroxydopamine (4 microL [8 microg]) to produce the Parkinson model lesion, and rotational testing was repeated. One group of the lesioned rats received a single intranigral injection of suspended fetal ventral mesencephalic cells (n = 11), and another received multiple intrastriatal grafts of the same type (n = 11).

RESULTS

Both grafted groups showed significant improvement on rotational testing with amphetamine and apomorphine at 6 weeks "postgrafting" (P < .001 for "postlesioning" vs postgrafting results in each of the 2 groups); however, the animals with multiple intrastriatal grafts showed complete recovery from motor asymmetry, whereas the rats with single intranigral grafts showed only partial improvement.

CONCLUSION

The findings indicate that multiple intrastriatal grafts result in significantly greater functional improvement than single intranigral grafts in this rat Parkinson model.

Experimental subarachnoid haemorrhage models in rats

There is no comprehensive and reliable model available in small animals that are suitable for the study of subarachnoid haemorrhage (SAH). In the study we reviewed the advantages and disadvantages of available SAH models in rats and presented our model. Experimental SAH was induced in a group of 350-450 g Sprague-Dawley rats. A 2 mm-diameter burr hole was drilled and, working under a microscope, haemorrhage was produced by transclival puncture of the basilar artery with a 20 microns thick piece of glass. The rats were assigned to either the experimental group (n: 7) or the control group (n: 7). Local cerebral blood flow (LCBF), intracranial pressure (ICP), and cerebral perfusion pressure (CPP) were measured for 60 min after SAH, after which the rats were decapitated. Microscopic examinations were done on three different segments of the basilar artery. There was a significant and sharp drop in LCBF just after SAH was induced (56.17 +/- 12.80 mlLD/min/100 g and 13.57 +/- 5.85 mlLD/min/100 g for baseline and post-SAH, respectively; p < 0.001), the flow slowly increased by the end of the experiment but never recovered to pre-SAH values (43.63 +/- 7.6 mlLD/min/100 g, p < 0.05). ICP (baseline 7.33 +/- 0.8 mmHg) increased acutely to 70.6 +/- 9.2 mmHg, and also returned to normal levels by 60 min after SAH. CPP (baseline 75.1 +/- 4.9 mmHg) dropped accordingly (to 21.0 +/- 6.3 mmHg) and then increased, reaching 70.1 +/- 4.9 mmHg at 60 min after SAH. Examinations of the arteries revealed decreased inner luminal diameter and distortion of the elastica layer. We present an inexpensive and reliable model of SAH in the rat that allows single and multiple haemorrhages and to study the early and late course of pathological changes.

Propofol versus isoflurane anesthesia under hypothermic conditions: effects on intracranial pressure and local cerebral blood flow after diffuse traumatic brain injury in the rat

BACKGROUND

The aim of this study was to compare the cerebral protective effects of two known protective anesthetics, isoflurane and propofol, when these were used in combination with moderate hypothermia (33-34 degrees C) after diffuse traumatic brain injury (TBI) in the rat. We assessed cerebral protection by measuring local cerebral blood flow (LCBF), mean arterial blood pressure (MABP), cerebral perfusion pressure (CPP) and intracranial pressure (ICP).

METHODS

Sixteen female Wistar rats weighing 275 to 350 g were anesthetized and subjected to an accelerated-impact weight-drop model of diffuse TBI. Hypothermia (33-34 degrees C) was induced 45 minutes after TBI (baseline), and was maintained for 180 minutes. The isoflurane group (n = 8) received 70% N(2)O in O(2), and isoflurane at 0.9 +/- 0.04%. The propofol group (n = 8) received 70% N(2)O in O(2) and a propofol infusion (12 mg/kg/hr). LCBF was measured by laser Doppler flowmeter. MABP, ICP, and brain and rectal temperatures were measured every 15 minutes from baseline through 180 minutes. Blood gas and hematocrit testing was also done at baseline and every 60 minutes thereafter to assess the animals' physiological state.

RESULTS

In the isoflurane group, MABP and CPP decreased significantly from baseline to 180 minutes (p < 0.05 and p < 0.01, respectively), and MABP was significantly lower than the pressure in the propofol group from 45 minutes through 180 minutes (p < 0.05, p < 0.01). ICP and LCBF remained unchanged in this group. In the propofol group, from baseline to 180 minutes, CPP increased to maximum 120 +/- 8 mmHg at 75 minutes from 98 +/- 5 mmHg (p < 0.05) and ICP fell from 18 +/- 2 mmHg to 7 +/- 1 mmHg (p < 0.01); and the latter was significantly lower than ICP in the isoflurane group (p < 0.05, p < 0.01, p < 0.001). LCBF in this group was significantly higher than LCBF in the isoflurane group in the last 30 minutes of the experiment (p < 0.05). The propofol group showed no change in MABP over the course of the experiment.

CONCLUSION

In the clinical setting, propofol anesthesia may be better for use in combination with hypothermia in cases of traumatic brain injury, as it reduces ICP and increases CPP under these conditions.

Acute and delayed vasoconstriction after subarachnoid hemorrhage: local cerebral blood flow, histopathology, and morphology in the rat basilar artery

The decreased local cerebral blood flow (LCBF) and cerebral ischemia that occur after subarachnoid hemorrhage (SAH) may be caused by acute and/or delayed vasospasm. In 36 Sprague-Dawley (350-450 g) rats SAH was induced by transclival puncture of the basilar artery. Mean arterial blood pressure (MABP), LCBF, intracranial pressure (ICP), and cerebral perfusion pressure (CPP) were measured in all rats for 30 min before and 60 min after SAH was induced. One set of control (n : 7) and experimental animals (n : 7) was sacrificed after the 60 min of initial post-hemorrhage measurements were recorded. Four days after SAH induction, LCBF and MABP were measured again for 60 min in subgroups of surviving experimental rats (n : 7) and control rats (n : 7). Histopathologic and morphologic examinations of the basilar artery were performed in each subgroup. There was a sharp drop in LCBF just after SAH was induced (55.50 +/- 11.46 mlLD/min/100 g and 16.1 +/- 3.6 mlLD/min/100 g for baseline and post-SAH, respectively; p < 0.001). The flow then gradually increased but had not returned to pre-SAH values by 60 min (p < 0.05). At 4 days after SAH induction, although LCBF was lower than that observed in the control group and pre-SAH values, it was not significantly different from either of these flow rates (p > 0.05). ICP (baseline 7.05 +/- 0.4 mmHg) increased acutely to 75.2 +/- 7.1 mmHg, but returned to normal levels by 60 min after SAH. CPP (baseline 84.5 +/- 6.3 mmHg) dropped accordingly (to 18.6 +/- 3.1 mmHg), and then increased, reaching 72.2 +/- 4.9 mmHg at 60 min after SAH (p > 0.05). Examinations of the arteries revealed decreased inner luminal diameter and distortion of the elastica layer in the early stage. LCBF in nonsurviver rats (n : 8) was lower than that in the animals that survived (p < 0.01). At 4 days post-hemorrhage, the rats' basilar arteries showed marked vasculopathy. The findings showed that acute SAH alters LCBF, ICP, and CPP, and that decreased LCBF affects mortality rate. Subsequent vasculopathy occurs in delayed fashion, and this was observed at 4 days after the hemorrhage event.

Effects of interrupted and uninterrupted occlusion of the basilar artery on cerebral blood flow, and on neurological and histological outcome in rats with subarachnoid hemorrhage

Most neurosurgeons consider temporary vessel occlusion for aneurysmal clipping an effective technique that facilitates dissection between the aneurysm and the parent vessel. It is generally believed that repeated short periods of cerebral ischemia are safer for the brain than a single long episode. The aim of this study was to identify whether interrupted and uninterrupted vessel occlusion differs with regard to changes in brain tissue and cerebral hemodynamics after subarachnoid hemorrhage (SAH). Fifty Spraque Dawley rats (300-350 g) were placed under general anaesthesia and ventilated. The basilar artery was exposed through a transclival approach. Baseline local cerebral blood flow (LCBF) values was measured, and then the basilar artery was punctured, causing subarachnoid hemorrhage (SAH). Group I (n = 24) was subjected to 60 min of interrupted basilar artery occlusion, defined as 5 min of reperfusion after every 10 min of occlusion, group II (n = 26) 60 min of uninterrupted artery occlusion. Three days after completion of the experiment, each rat was neurologically evaluated and decapitated. Coronal brain slices were obtained and stained to assess infarct volume. Immediately after SAH, LCBF fell by 58% in group I, and by 52% in group II. In group I, each ischemic insult brought a similar reduction in LCBF, and after each release of the occlusion there was a rapid rise in flow. In group II, the LCBF values dropped initially and remained at low levels until the end of the study. The 2,3,5 triphenyltetrazolium chloride stained sections showed similar volumes of brainstem infarction in both groups (38.3 +/- 9.2 mm3 vs. 34.3 +/- 8.7 mm3, respectively; p > 0.05). The results suggest that there is no neuroprotective advantage to either interrupted or uninterrupted temporary blockage of blood flow during neurovascular procedures after SAH in the basilar artery region.

The effects of sevoflurane and isoflurane on intracranial pressure and cerebral perfusion pressure after diffuse brain injury in rats

Twenty-four adult male Wistar rats, weighing 220 to 290 g, were anesthetized with 30 mg/kg intraperitoneal sodium thiopental, then underwent a tracheostomy. After diffuse impact-acceleration brain injury (BI) was induced, each rat was paralyzed and mechanically ventilated with 30% O2 in nitrous oxide (N2O). The rats were assigned randomly to two groups, each of which received one of the two volatile anesthetic agents, sevoflurane or isoflurane. The anesthetics were administered at 0.5, 0.75, 1.0, and 1.25 minimal alveolar concentration (MAC) for 30 minutes each, respectively, and anesthesia was maintained at 0.75 MAC during the last hour of the study period. Intracranial pressure (ICP), mean arterial pressure (MAP), rectal and intrahemispheric temperatures, and end-tidal volatile anesthetic concentrations were monitored continuously throughout the 3 hours, with measurements recorded every 15 minutes. At baseline, there were no significant differences between the two groups regarding the monitored physiologic values. In the sevoflurane group, MAP fell significantly after 45 minutes, and a similar change was observed in the isoflurane group after 30 minutes (P < .05, P < .01, and P < .001, respectively). Intracranial pressure increased significantly at 45 minutes in the sevoflurane group (P < .01) and remained elevated from 60 minutes until the end of the study period (P < .01, P < .001). Although ICP increased in the isoflurane group, the change was not significant. Cerebral perfusion pressure (CPP) decreased in parallel with MAP, with the reduction in the sevoflurane group being more pronounced than that in the isoflurane group. The results demonstrated that, under the conditions of diffuse BI, animals that were anesthetized with sevoflurane had higher ICP and lower CPP levels than those anesthetized with isoflurane.

Neuroprotective effects of MK 801 and hypothermia used alone and in combination in hypoxic-ischemic brain injury in neonatal rats

Although accumulating evidence suggests that increased extracellular glutamate concentrations may play an important role in hypoxic-ischemic brain injury, dopamine and other catecholamines also seem to be involved. The N-methyl-D-aspartate receptor antagonist MK 801 and moderate hypothermia (32-34 degrees C) are each known to be neuroprotective, but their combined effect on the release and metabolism of neurotransmitters is unknown. Seven-day-old pups (n: 150) underwent right common carotid artery ligation to induce hemispheric ischemia, and were later subjected to 120 minutes of hypoxia with 8% O2 and 92% N2O. Half the rats (Group I, n: 74) were subjected to normothermic conditions throughout the hypoxic period. Moderate hypothermia (30-32 degrees C) was induced in the other pups (Group II, n: 76) immediately after artery occlusion, and was maintained throughout the hypoxic period. Prior to inducing hypoxia, half of the rats in each group (Groups IA and IIA) received vehicle solution (0.9% NaCI) and the other rats (Groups IB and IIB) received MK 801 (0.5 mg/kg) subcutaneously at 45 and 120 minutes after occlusion. Intracerebral temperature was recorded every 15 minutes after occlusion. Infarct area (n: 40) was calculated after staining with 2% 2,3,5 triphenyltetrazolium chloride. Neuronal damage (n: 42) was assessed by quantifying CA1-CA3 neuronal loss at five hippocampal levels. The amount of damage to the monoamine system of the corpus striatum was determined based on the dopamine and 3,4 dihydroxyphenylacetic acid levels in the corpus striatum in both hemispheres (n: 46), as measured by high-pressure liquid chromatography and compared with normal control pups' values (n: 10). The normothermia/saline-treated pups had significantly larger infarct areas than the MK 801 only, hypothermia only, or MK 801/hypothermia combination groups. Neuropathological examination and striatal tissue monoamine data also confirmed marked neuronal damage in this group. Although MK 801 treatment alone resulted in significantly smaller infarct area and less tissue damage than was observed in the normothermia/saline-treated group, the moderate hypothermia and the MK 801/hypothermia combination treatment groups both exhibited better neuronal protection, especially in the corpus striatum. The rats that received combined treatment also had a significantly lower mortality rate.

Ischemic brain injury caused by interrupted versus uninterrupted occlusion in hypotensive rats with subarachnoid hemorrhage: neuroprotective effects of citicoline

This study investigated the neuroprotection provided by cytidine 5'-diphosphocholine (citicoline) during interrupted and uninterrupted occlusion of the basilar artery after subarachnoid hemorrhage (SAH) in 121 hypotensive rats. Animals were anesthetized and the basilar artery was exposed through a transclival approach. Baseline local cerebral blood flow (LCBF) values were recorded, and then the basilar artery was punctured, causing SAH. Blood was drawn to induce hypotension [60-70 mmHg mean arterial blood pressure (MABP)]. Control rats received intraperitoneal (i.p.) injections of 0.5 ml saline immediately after SAH before hypotension induction and after 60 min of occlusion. Experimental rats received 400-mg/kg citicoline i.p. at the same time points. Control group I and treatment group III were subjected to 60 min of interrupted occlusion (5 min of reperfusion after each 10 min of occlusion). Control group II and treatment group IV were subjected to 60 min of uninterrupted occlusion. MABP and LCBF were recorded every 5 minutes. Brain edema was evaluated in seven rats from each group at 24 hours after ischemic injury. At 3 days after occlusion, another set of 28 rats was killed and coronal brain slices were stained to assess infarct volume. The groups' physiological and edema findings were similar. In all groups, LCBF fell immediately after SAH and remained below baseline throughout the experiment. In the citicoline-treated rats, arterial pressure increased significantly after 30-40 min of occlusion, and brain slices showed significantly smaller infarct volumes compared to control slices (p < 0.05). Mortality was significantly lower in the citicoline-treated animals (p < 0.001). The results suggest that citicoline provides significant neuroprotection during cerebral ischemia, and that it significantly reduces mortality. Part of the neuroprotective effect may be mediated by recovery of arterial pressure.

An anatomical and pathological evaluation of middle cerebral artery occlusion in rats

Adult male Sprague-Dawley rats (n = 87) weighing 350-400 g were used for studying the anatomy of the horizontal segment of middle cerebral artery and infarct area after occlusion of the artery. In the experimental group (n = 27) middle cerebral artery was coagulated 3-4 mm length from the origin of the lateral striate arteries to the inferior cerebral vein and divided. Control rats (n = 20) had all the surgical procedures except occlusion. Another group of rats (n = 40) were used to determine the anatomical variations of middle cerebral artery after intracarotid carbon black injection. Five major patterns of middle cerebral artery were observed and two of them were major and constituted 92.5% of rats. Twenty-four hours after middle cerebral artery occlusion, all animals were neurologically evaluated. On the third day after occlusion the brains were stained with 2%, 2,3,5-triphenyltetrozolium chloride. The area of infarction was assessed by computerized analysis method. In our study after determining the variations of the middle cerebral artery and its branches in our strain of rats, we were able to achieve 92.5% grade III and IV infarcted area.