Changes In Rat Brain Research Articles

A Novel Isoform of the Secretory Pathway Ca2+,Mn2+-ATPase, hSPCA2, Has Unusual Properties and Is Expressed in the Brain

Unlike lower eukaryotes, mammalian genomes have a second gene, ATP2C2, encoding a putative member of the family of secretory pathway Ca2+,Mn(2+)-ATPases, SPCA2. Human SPCA2 shares 64% amino acid identity with the protein defective in Hailey Hailey disease, hSPCA1. We show that human SPCA2 (hSPCA2) has a more limited tissue distribution than hSPCA1, with prominent protein expression in brain and testis. In primary neuronal cells, endogenous SPCA2 has a highly punctate distribution that overlaps with vesicles derived from the trans-Golgi network and is thus different from the compact perinuclear distribution of hSPCA1 seen in keratinocytes and nonpolarized cells. Heterologous expression in a yeast strain lacking endogenous Ca2+ pumps reveals further functional differences from hSPCA1. Although the Mn(2+)-specific phenotype of hSPCA2 is similar to that of hSPCA1, Ca2+ ions are transported with much poorer affinity, resulting in only weak complementation of Ca(2+)-specific yeast phenotypes. These observations suggest that SPCA2 may have a more specialized role in mammalian cells, possibly in cellular detoxification of Mn2+ ions, similar to that in yeast. We point to the close links between manganese neurotoxicity and Parkinsonism that would predict an important physiological role for SPCA2 in the brain.

Protein oxidative damage in arsenic induced rat brain: influence of dl-α-lipoic acid

A body of evidence has accumulated implicating free radical generation and reaction of arsenic with protein thiols in the biochemical and molecular mechanisms of arsenic toxicity. Brain readily undergoes oxidative damage, so it is important to determine whether arsenic-induced changes in rat brain may be associated with oxidative events. An increase in oxidative stress may contribute to the development of protein damage in rat brain. Present experiments were performed to study the effect of arsenic (sodium arsenite, 100 ppm mixed in drinking water) on protein oxidation and further to demonstrate the potential of dl-α-lipoic acid (70 mg/kg body weight) against arsenic-induced changes in different anatomic regions (cortex, striatum, cerebellum, hypothalamus and hippocampus) of the brain of male Wistar rats. We report here that arsenic treated rats had a significantly higher level of oxidised protein as assessed by increased carbonyl residues and decreased protein thiols (protein sulfhydryls) as compared to control rats in all five regions studied, with the most notable changes occurring in the cortex, striatum and hippocampus. Coadministration of lipoic acid along with arsenic resulted in reversal of the arsenic induced trends in carbonyl and sulfhydryl concentrations. The results of the study showed, lipoic acid treatment reduces oxidative protein damage in arsenic intoxicated rat brain regions, which is associated with its antioxidant activity that combines free radical scavenging and metal chelating properties.

Chronic cerebral hypoperfusion and reperfusion injury of restoration of normal perfusion pressure contributes to the neuropathological changes in rat brain

Chronic cerebral hypoperfusion and reperfusion injury of restoration of normal perfusion pressure contributes to the neuropathological changes in rat brain

Chronic cerebral hypoperfusion and reperfusion injury of restoration of normal perfusion pressure contributes to the neuropathological changes in rat brain

Restoration of normal perfusion pressure after resection of cerebral arteriovenous maformations (AVMs) is sometimes complicated by unexplained postoperative brain swelling and/or intracranial hemorrhage, which has been termed normal perfusion pressure breakthrough (NPPB). The precise mechanism of NPPB is still unclear. In this study, we investigated the time courses of blood–brain barrier (BBB) disruption, water content, neuronal apoptosis, myeloperoxidase (MPO) activity and superoxide dismutase (SOD) activity in the brain during restoration of normal perfusion pressure in a new rat model of chronic cerebral hypoperfusion associated with AVMs. Male Sprague–Dawley rats were randomly divided into either a sham-operated group, a control group, or a model group with reperfusion assessed at 1, 12, 24 and 72 h after restoration of normal perfusion pressure. BBB disruption was judged by extravasation of Evans blue (EB) dye. We observed that EB and water content in rat brains of the model group with reperfusion were significantly increased compared with the other groups. The most predominant increase occurred at 1 h after reperfusion, and the next at 24 h after reperfusion, representing biphasic changes which are similar to the pathological processes of acute cerebral ischemia/reperfusion injury. There was no difference of the percentage of apoptotic cells in rat brains between the sham-operated group and the control group using flow cytometry. No prominent apoptotic cells were found in the model group with reperfusion at 1 h. However, the percentage of apoptotic cells increased significantly in rat brains of the model group with reperfusion at 12 h, peaked at 24 h, and decreased at 72 h after reperfusion. Apoptotic cells were confirmed with electron microscopy and terminal deoxynuleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). A significant enhancement of MPO activity in combination with reduction of SOD activity was seen at 12, 24 and 72 h in rat brains of the model group with reperfusion. Our data indicates that reperfusion after restoration of normal perfusion pressure with chronic cerebral hypoperfusion lead to secondary neuronal damage which may associate with cerebral ischemia/reperfusion injury.

OPIOID NEUROTOXICITY: COMPARISON OF MORPHINE AND TRAMADOL IN AN EXPERIMENTAL RAT MODEL

Histopathologic changes in rat brain due to chronic use of morphine and/or tramadol in progressively increased doses were investigated in this study. Thirty male Wistar rats (180-220 g) were included and divided into three groups. Normal saline (1 ml/kg) was given intraperitoneally as placebo in the control group (n = 10). Morphine group (n = 10) received morphine intraperitoneally at a dose of 4 mg/kg/day for the first 10 days, 8 mg/kg/day between 11-20 days, and 12 mg/kg/day between 21-30 days. The tramadol group (n = 10) received the drug intraperitoneally at doses of 20, 40, and 80 mg/kg/day in the first, second, and the third 10 days of the study, respectively. All rats were decapitated on the 30th day and the brain was removed intact for histology. The presence and the number of red neurons, which are a histologic marker of apoptosis, were investigated in the parietal, frontal, temporal, occipital, entorhinal, pyriform, and hippocampal CA1, CA2, CA3 regions. Red neurons were found in morphine and tramadol groups but not in the control group. The total number of red neurons was not different in morphine and tramadol groups, but the numbers of red neurons were significantly higher in the temporal and occipital regions in tramadol group as compared with the morphine group (p < .05). In conclusion, chronic use of morphine and/or tramadol in increasing doses is found to cause red neuron degeneration in the rat brain, which probably contributes to cerebral dysfunction. These findings should be taken into consideration when chrome use of opioids is indicated.

1-Methyl-1,2,3,4-tetrahydroisoquinoline protects against rotenone-induced mortality and biochemical changes in rat brain

The effect of single and multiple administration of the neurotoxic pesticide, rotenone, and the potentially neuroprotective compound, 1-methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ), on the concentration of dopamine and its metabolites (homovanillic acid-HVA, 3,4-dihydroxyphenylacetic acid-DOPAC, and 3-methoxytyramine-3-MT)) in three brain areas was studied by high-performance liquid chromatography (HPLC) with electrochemical detection in Wistar rats. The rate of dopamine catabolism in the striatum along the N-oxidative and O-methylation pathways was assessed by calculation of the ratio of dopamine metabolites to dopamine. In addition, the effect of rotenone on mortality and general behavior of rats was investigated. We have found that the neurotoxic pesticide, rotenone, administered in a single dose (12 mg/kg s.c.) did not produce evident behavioral or biochemical effects. In contrast, repeated administration of rotenone in doses (12–15 mg/kg) causing abnormalities in general behavior, produced considerable mortality and dramatic increases in dopamine metabolism, which may be ascribed to an increase in the oxidative pathway. Interestingly, it depressed the concentration of the extracellular dopamine metabolite, 3-MT. These behavioral and biochemical changes were effectively counteracted by administration of 1MeTIQ before each dose of rotenone. In summary, we demonstrated that multiple systemic rotenone injections are strongly toxic, and induce alterations of cerebral dopamine metabolism, and that 1MeTIQ may be considered as a potential protective agent against environmental factors affecting the function of the dopaminergic system.

In vivo monitoring of age-related changes in rat brain using quantitative diffusion magnetic resonance imaging and magnetic resonance relaxometry

Diffusion-weighted magnetic resonance imaging (MRI) has been proven to be a sensitive diagnostic tool to examine age associated acute and chronic changes in brain tissue. The aim of our study was to examine whether there are differences in brain diffusion and transverse relaxation time between young and adult rats. In an experimental MR scanner, 24 young (age: 3 months) and 26 adult rats (age: 12 months) were examined using diffusion-weighted and transverse relaxation time (T2)-weighted MRI sequences. There were no differences in the T2 relaxation time between the two animal groups, either local or global. However, the mean apparent diffusion coefficient (ADC) within the whole brain was significantly lower (P<0.0005) in the adult animals (765±35×10−6 mm2/s) than in the young animals (829±45×10−6 mm2/s). ADC decrease was mainly found in the cerebral cortex. These results can be attributed to an activity-related or central nervous system damage-related internal water shift from the extracellular to the intracellular space without a net increase in water content in brain tissue. Our study also shows that age-related changes in diffusion should be considered when performing longitudinal studies in rats.

Pilocarpine-induced epileptogenesis in the rat:: Impact of initial duration of status epilepticus on electrophysiological and neuropathological alterations

This study characterized the electrophysiological and neuropathological changes in rat brains caused by pilocarpine (PILO)-induced status epilepticus (SE) of different duration. SE induced by PILO (375 mg/kg, i.p. adm.) were terminated with a bolus dose of diazepam (10 mg/kg, i.v. adm.) injected 7.5, 15, 30, 60 or 120 min after initiation of the secondary generalization of the SE. Three weeks later, the gain in body weight was significantly reduced in the rats exposed to PILO-induced SE lasting 30 min or more, when compared to controls. Spontaneous seizures were not detected in rats with PILO-induced SE of 7.5 min duration whereas 50 and 25% of the rats exposed to seizure durations of 30 and 120 min expressed motor seizures. Significant alterations reflecting hyperexcitability (increased number of population spikes (PSs)) and reduced paired-pulse inhibition were observed in recordings of hippocampal field potentials from rats with PILO-induced SE of at least 30 min duration. This was substantiated by brain lesions (necrosis in olfactory cortex, hippocampus, amygdala and thalamus) in all rats manifesting a SE of at least 30 min duration. Thus, the results of the present study demonstrate that rats exposed to PILO-induced SE of at least 30 min duration manifest an epileptogenic process, revealed 3 weeks later by several parameters. Among these, hippocampal field potentials appear to represent the most sensitive marker, potentially useful for pharmacological evaluation of drugs with putative antiepileptogenic properties.

Influence of Age on Aluminum-Induced Neurobehavioral Effects and Morphological Changes in Rat Brain

Aluminum (Al) is potentially toxic for mammals. In contrast to well documented Al neurotoxicity, neurobehavioral studies of Al in rodents have generally not produced robust or consistent results. In the present study, 16 young male (21 days old) and 16 old male (18 months) rats were exposed to 0 (control group) and 100 mg/kg/day of Al administered as Al nitrate nonahydrate in drinking water concurrently with citric acid (356 mg/kg/day) for a period of 100 days. At the end of the exposure period, rats were evaluated for motor activity in an open-field apparatus and learning in a passive avoidance test. After behavioral testing, rats were sacrificed and brain samples were collected to determine Al concentrations and to study synapses in the left CA1 fields of hippocampal formation. While no significant effects of Al exposure between groups could be detected on behavior, the total number of synapses decreased with age and Al exposure. In turn, the percentage of perforated synapses significantly increased in old Al-loaded rats.

MAGNETICALLY RESTRUCTURED WATER INDUCES CHANGES IN RAT BRAIN

Fifty-hertz power line-treated magnetically restructured water induced changes in rat brain was studied. Triple-distilled water samples were exposed to 36.2 RMS and (51.2 peak) μT power line magnetic fields for 48 hr. This magnetized water sample was given to adult male rats of Charles–Foster strain for drinking ad libitum for a period of 30 days, at the end of which the rats were anaesthetized with ether and then fixed by perfusion with 10% neutral formalin. The brains were dissected out and further fixed in the same fixative. The corresponding control rats provided with unmagnetized triple-distilled water were similarly treated. On gross examination, no anomaly was observed in the treated group. On histological examination, marked spongiform changes leading to neuronal degeneration were observed in cerebral and hippocampal cortices. The study adds a further link in demonstrating that power line exposure induced stable changes in water structures affect biomechanisms of tissue fluids.

Propofol and sodium thiopental protect against MK-801-induced neuronal necrosis in the posterior cingulate/retrosplenial cortex

N-Methyl- d-aspartate (NMDA) antagonists act by an anti-excitotoxic action to provide neuroprotection against acute brain injury, but these agents can also cause toxic effects. In low doses they induce reversible neuronal injury, but in higher doses they cause irreversible degeneration of cerebrocortical neurons. GABAmimetic drugs protect against the reversible neurotoxic changes in rat brain. Here we show that two GABAmimetic anesthetic agents — propofol and sodium thiopental — protect against the irreversible neurodegenerative reaction induced by the powerful NMDA antagonist, MK-801.

Metabolic changes in rat brain after prolonged ethanol consumption measured by 1H and 31P MRS experiments.

1. In vivo 1H and 31P magnetic resonance spectroscopy techniques were applied to reveal biochemical changes in the rat brain caused by prolonged ethanol consumption. 2. Three models of ethanol intoxication were used. 3. 1H MRS showed a significant decrease in the concentration of myo-inositol in the brain of rats fed with 20% ethanol for 8 weeks. This change is consistent with perturbances in astrocytes. On the other hand, N-acetyl aspartate and choline content did not differ from controls. 4. 31P MRS did not reveal any significant changes in the high-energy phosphates or intracellular free Mg2+ content in the brain of rats after 14 weeks of 20% ethanol drinking. The intracellular pH was diminished. 5. By means of a 31P saturation transfer technique, a significant decrease was observed for the pseudo first-order rate constant k(for) of the creatine kinase reaction in the brain of rats administered 30% ethanol for 3 weeks using a gastric tube. 6. The 1H MRS results may indicate that myo-inositol loss, reflecting a disorder in astrocytes, might be one of the first changes associated with alcoholism, which could be detected in the brain by means of in vivo 1H MRS. 7. The results from 31p MRS experiments suggest that alcoholism is associated with decreased brain energy metabolism. 8. 31P saturation transfer, which provides insight into the turnover of high-energy phosphates, could be a more suitable technique for studying the brain energetics in chronic pathological states than conventional 31P MRS.

Ultrastructural and Immunohistochemical Changes of Rat Brain after Long-Term Marijuana Inhalation.

Ultrastructural changes of the brain of rats that inhaled marijuana cigarettes for 8 weeks were examined by electron microscopy, simultaneously with immunohistochemical investigation for serotonergic neuronal activities in the nucleus accumbens (NAc), the hippocampus (CA-1) and the nucleus raphe dorsalis (NRD). In the animals that inhaled marijuana, numerous cored and coated vesicles were observed near the well-developed Golgi apparatus of the NRD neurons. The lamellar membranous structure was found frequently in the dendrite, and occasionally in the axon, and the synapse of the marijuana-smoking animals. The serotonin-immunostainability in neurons of the NRD was significantly stronger in the animals that inhaled marijuana than in the non-treated ones. The serotonin-immunostainability in nerve fibers and terminals of the NAc and the CA-1 showed an obvious decrease compared with that of the non-treated animals. These findings suggest that the neurons in the NRD that is the original nucleus of the serotonergic nerve system have become functionally hyperactive by Δ9-tetrahydrocannabinol, but it may induce the dysfunction of serotonin transmission from the original nucleus.

Hypericum perforatum L. extract does not inhibit 5-HT transporter in rat brain cortex.

The hydroalcoholic extract of Hypericum perforatum L. is an effective antidepressant, although its mechanism of action is still unknown. It inhibits the synaptosomal uptake of serotonin (5-HT), dopamine and noradrenaline, suggesting a biochemical mechanism similar to the synthetic standard antidepressants. In the present study, further investigating this hypothesis, we confirmed that a hydromethanolic extract of H. perforatum inhibited [3H]5-HT accumulation in rat brain cortical synaptosomes with an IC50 value of 7.9 microg/ml. The IC50 of pure hyperforin was 1.8 microg/ml, so the activity of the total extract is not related only to its hyperforin content (<5%). This inhibitory effect, however, is not due to a direct interaction with, and blockade of, the 5-HT transporters since the extract, like hyperforin, did not inhibit [3H]citalopram binding (IC50 > 100 microg/ml and 10 microg/ml, respectively). We also found that 3-10 microg/ml of the extract, or 0.3-1 microg/ml hyperforin, induced marked tritium release from superfused synaptosomes previously loaded with [3H]5-HT. The releasing effect of the extract resembles the releasing effect of a reserpine-like compound (Ro 04-1284), i.e. it was slightly delayed and was 5-HT carrier- and calcium-independent. These data suggest that the hydromethanolic extract of H. peforatum, similarly to Ro 04-1284, rapidly depletes storage vesicles, raising the cytoplasmic concentration of 5-HT, and this increase is presumably responsible for the apparent inhibition of [3H]5-HT uptake. Therefore, our in vitro data do not confirm that the hydromethanolic extract of H. perforatum acts as a classical 5-HT uptake inhibitor but indicate reserpine-like properties. However, the concentrations of the active component(s) effective in vitro as reserpine-like agent(s) (i.e. corresponding to > or =3 microg/ml of the hydromethanolic extract) do not seem to be achieved in the brain after pharmacologically effective doses of the extract, as indicated by the finding that there were no significant changes of rat brain 5-HT and 5-hydroxyindoleacetic acid levels after a schedule of treatment (3 x 300 mg/kgday, orally) active in an animal model predictive of antidepressant-like activity. These data also suggest that the antidepressant effect of H. perforatum extracts is unlikely to be associated with interaction with GABA, benzodiazepine and 5-HT1 receptors since, in receptor binding studies, we found IC50 values higher than 5 microg/ml. Therefore other, still unknown, mechanisms are possibly involved in H. perforatum antidepressant effects.

Apparent Diffusion Coefficient on Rat Brain and Nerves Intoxicated with Methylmercury

The effects of methylmercury chloride (MMC) on the degenerative changes in rat brain and cranial nerves were studied. Twelve Wistar rats were divided into two equal groups. The rat model of methylmercury intoxication (MMC group) was made by subcutaneously administering 10 mg mercury/g body weight daily for 7 days. Control group rats were infused with the same amount of normal saline during this period. Magnetic resonance imaging (MRI) measurements were performed before and 14 days after the first MMC administration, using a 4.7-T MR system. No significant focal changes were observed on T1- and T2-weighted MR images regarding the internal structures of the brains of the MMC-intoxicated rats, atrophy of the cerebellum, and dilatation of the arachnoid space around the brain stem of MMC-treated rats, but were demonstrated without edematous change. The apparent diffusion coefficients (ADC) of the cortex, caudate-putamen, and trigeminal nerve were not significantly different between the MMC-treated and control rats. However, the ADC parallel to the optic nerves were significantly increased in the MMC group, in contrast to the unchanged ADC perpendicular to the optic nerves. An electron microscopy study revealed a marked decrease of microtubules and moderate decrease of neurofilaments in the axons of myelinated fibers of optic nerves of the MMC-treated rats. We have thus demonstrated a disturbance in the integrity of microtubules and neurofilaments as a toxic action of MMC in the rat nervous systemin vivo, particularly in the optic nerves. The use of ADC values calculated by diffusion-weighted MRI is a promising approach for the evaluation of changes in brains and nerves in methylmercury intoxication research.

Detection of hypoxic cells with the 2-nitroimidazole, EF5, correlates with early redox changes in rat brain after perinatal hypoxia–ischemia

The hypoxia-dependent activation of nitroheterocyclic drugs by cellular nitroreductases leads to the formation of intracellular adducts between the drugs and cellular macromolecules. Because this covalent binding is maximal in the absence of oxygen, detection of bound adducts provides an assay for estimating the degree of cellular hypoxia in vivo. Using a pentafluorinated derivative of etanidazole called EF5, we studied the distribution of EF5 adducts in seven-day-old rats subjected to different treatments which decrease the level of oxygen in the brain. EF5 solution was administered intraperitoneally 30 min prior to each treatment. The effect of acute and chronic hypoxia on EF5 adduct formation (binding) was studied in the brain of newborn rats exposed to global hypoxia (8% O 2 for 30, 90 or 150 min) and in the brain of chronically hypoxic rat pups with congenital cardiac defects (Wistar Kyoto). The effect of combined hypoxia–ischemia was investigated in rat pups subjected to right carotid coagulation and concurrent exposure to 8% O 2 for 30, 90 or 150 min. Brains were frozen immediately at the end of each treatment. Using a Cy3-conjugated monoclonal mouse antibody (ELK3-51) raised against EF5 adducts, hypoxic cells within brain regions were visualized by fluorescence immunocytochemistry. Brains from controls or vehicle-injected animals showed no EF5 binding. Notably, brains from animals which were chronically hypoxemic as a result of congenital cardiac defects also showed no EF5 binding. A short exposure (30 min) to hypoxia or to combined hypoxia–ischemia resulted in increased background stain and few scattered cells with low-intensity immunostaining. Acute hypoxia exposure of at least 90–150 min, which in this age animal does not result in frank cellular damage, produced patchy areas of low- to moderate-intensity fluorescence scattered throughout the brain. In contrast, 90–150 min of hypoxia–ischemia was associated with intense immunofluorescence in the hemisphere ipsilateral to the carotid occlusion, with a pattern similar to that reported previously for the histological damage seen in this model. This study provides a sensitive method for the evaluation of the level of oxygen depletion in brain tissue after neonatal hypoxia–ischemia, at times much earlier than any method demonstrates apoptotic or necrotic cell death. Since the level of in vivo formation of macromolecular adducts of EF5 depends on the degree of oxygen depletion in a tissue, intracellular EF5 binding may serve as a useful marker of regional cellular vulnerability and redox state after brain injury resulting from hypoxia–ischemia.

Non-Invasive Imaging of Absorption Changes in Rat Brain by NIR Transillumination

Non-Invasive Imaging of Absorption Changes in Rat Brain by NIR Transillumination

Structural changes in rat brains after electroconvulsive treatment (ECT) and transcranial magnetic stimulation (TMS)

Structural changes in rat brains after electroconvulsive treatment (ECT) and transcranial magnetic stimulation (TMS)

MRS metabolic markers of seizures and seizure-induced neuronal damage.

Proton magnetic resonance spectroscopy (MRS) was used to identify specific in situ metabolic markers for seizures and seizure-induced neuronal damage. Kainic acid (KA)-induced seizures lead to histopathologic changes in rat brain. The protective effect of cycloheximide treatment against neuronal damage caused by KA-induced seizures was studied, using in situ proton MRS imaging technique. Rats were pretreated with placebo or cycloheximide 1 h before KA injection. Rat brains (n = 25) were scanned at the level of the hippocampus before, during, and 24 h after seizures. Spectra were recorded and the relative ratios of N-acetylaspartate (NAA), choline (cho), and lactate (Lac) to creatine (Cr) were calculated and compared between groups. A significant increase in Lac ratios was observed in KA-treated rats during and 24 h after seizure onset and this increase was prevented by cycloheximide pretreatment. NAA ratios were significantly higher during the ictal phase following KA treatment and this effect was not affected by cycloheximide pretreatment. Nissl staining confirmed previously reported prevention of KA-induced neuronal loss in CA3 and CA1 areas of the hippocampus by cycloheximide pretreatment. Our results suggest that in situ Lac increase is a marker of seizure-induced neuronal damage, whereas N-acetylaspartate (NAA) changes during and after status epilepticus may be a reflection of neuronal activity and damage, respectively.

Lesion of nigrostriatal neurons by 6-hydroxydopamine induces changes in rat brain glutathione-S-transferase.

Wistar rats were lesioned into the nigrostriatal pathway with 6-OHDA. The D-amphetamine-induced circling behavior test was performed to evaluated lesion efficiency. Animals that showed more than 620 turns/90 min were named totally lesioned animals (TLA). The group of rats that performed less than 620 turns/90 min were named partially lesioned animals (PLA). The contents of DA and its catabolites in the striata of these groups, and in the same tissue of the untreated animals, were measured. Moreover, the striatal glutathione-S-transferase (GST) specific activity for all groups was tested, and the kinetics parameters for GST purified from the whole brain were evaluated from other three similar groups. The striatal DA depletion on TLA was greater than in PLA. Striatal GST activity showed a significantly bilateral increase in PLA, whereas TLA exhibited only and ipsilateral augment. There were also differences between groups about the kinetic parameters of the purified brain enzyme. The possible role of GST on the interindividual lesion response difference was analyzed.