Influence of substitutive ovarian steroids in the nuclear and cell body volumes of neurons in the posterodorsal medial amygdala of adult ovariectomized female rats

The volumes of the neuronal nucleus and the cell body in the left posterodorsal medial amygdala (MePD) of adult ovariectomized (OVX) female rats submitted to different hormonal therapies were studied here, aiming to reveal possible influence of substitutive sex steroids in these morphological parameters. One week following ovariectomy and at the end of treatments, brains were cut to semi-thin sections (1 microm) and stained with 1% toluidine blue for stereological estimations, carried out using the Cavalieri method and the technique of point counting. Both the volume of the neuronal nucleus and the soma showed a statistically significant difference when comparing the data among OVX females treated with vehicle (V), estradiol (EB) alone, EB plus progesterone (EB+P) or P alone [n=5 rats in each group; one-way ANOVA test, P<0.01 in both cases]. The Tukey test showed that OVX and EB+P treated females had higher mean neuronal nucleus and somatic volumes when compared to V (P<0.01) or EB alone (P<0.01). Also, OVX females treated with P alone showed larger mean neuronal nucleus and somatic volumes when compared to V (P<0.05). These results suggest that the neuronal nucleus and the somatic volumes can be modulated by substitutive ovarian hormones administered to OVX females, for which P can lead to higher results. These findings reveal additional epigenetic actions of the sex steroids in the MePD and new neuronal morphological features in adult female rats.

Ultrastructural features of the columellar muscle and contractile protein analyses in different muscle groups of Megalobulimus abbreviatus (Gastropoda, Pulmonata)

In Megalobulimus abbreviatus, the ultrastructural features and the contractile proteins of columellar, pharyngeal and foot retractor muscles were studied. These muscles are formed from muscular fascicles distributed in different planes that are separated by connective tissue rich in collagen fibrils. These cells contain thick and thin filaments, the latter being attached to dense bodies, lysosomes, sarcoplasmic reticulum, caveolae, mitochondria and glycogen granules. Three types of muscle cells were distinguished: T1 cells displayed the largest amount of glycogen and an intermediate number of mitochondria, suggesting the highest anaerobic metabolism; T2 cells had the largest number of mitochondria and less glycogen, which suggests an aerobic metabolism; T3 cells showed intermediate glycogen volumes, suggesting an intermediate anaerobic metabolism. The myofilaments in the pedal muscle contained paramyosin measuring between 40 and 80nm in diameter. Western Blot muscle analysis showed a 46-kDa band that corresponds to actin and a 220-kDa band that corresponds to myosin filaments. The thick filament used in the electrophoresis showed a protein band of 100kDa in the muscles, which may correspond to paramyosin.

Hippocampal alterations in rats submitted to streptozotocin-induced dementia model are prevented by aminoguanidine

Although the exact cause of Alzheimer's disease remains elusive, many possible risk factors and pathological alterations have been used in the elaboration of in vitro and in vivo models of this disease in rodents, including intracerebral infusion of streptozotocin (STZ). Using this model, we evaluated spatial cognitive deficit and neurochemical hippocampal alterations, particularly astroglial protein markers such as glial fibrillary acidic protein (GFAP) and S100B, glutathione content, nitric oxide production, and cerebrospinal fluid (CSF) S100B. In addition, prevention of these alterations by aminoguanidine administration was evaluated. Results confirm a spatial cognitive deficit and nitrative stress in this dementia model as well as specific astroglial alterations, particularly S100B accumulation in the hippocampus and decreased CSF S100B. The hippocampal astroglial activation occurred independently of the significant alteration in GFAP content. Moreover, all these alterations were completely prevented by aminoguanidine administration, confirming the neuroprotective potential of this compound, but suggesting that nitrative stress and/or glycation may be underlying these alterations. These findings contribute to the understanding of diseases accompanied by cognitive deficits and the STZ-model of dementia.

Morphological changes in hippocampal astrocytes induced by environmental enrichment in mice

Environmental enrichment is known to induce plastic changes in the brain, including morphological changes in hippocampal neurons, with increases in synaptic and spine densities. In recent years, the evidence for a role of astrocytes in regulating synaptic transmission and plasticity has increased, and it is likely that morphological and functional changes in astrocytes play an important role in brain plasticity. Our study was designed to evaluate changes in astrocytes induced by environmental enrichment in the CA1 region of the hippocampus, focusing on astrocytic density and on morphological changes in astrocytic processes. After 8 weeks of environmental enrichment starting at weaning, male CF-1 mice presented no significant changes in astrocyte number or in the density of glial fibrillary acidic protein (GFAP) immunoreactivity in the stratum radiatum. However, they did present changes in astrocytic morphology in the same region, as expressed by a significant increase in the ramification of astrocytic processes measured by the Sholl concentric circles method, as well as by an increase in the number and length of primary processes extending in a parallel orientation to CA1 nerve fibers. This led astrocytes to acquire a more stellate morphology, a fact which could be related to the increase in hippocampal synaptic density observed in previous studies. These findings corroborate the idea that structural changes in astrocytic networks are an integral part of plasticity processes occurring in the brain.

Endurance and resistance exercise training programs elicit specific effects on sciatic nerve regeneration after experimental traumatic lesion in rats

OBJECTIVE

To evaluate the effects of endurance, resistance, and a combination of both types of exercise training on hindlimb motor function recovery and nerve regeneration after experimental sciatic nerve lesion in rats.

METHODS

Sciatic nerve crush was performed on adult male rats, and after 2 weeks of the nerve lesion, the animals were submitted to endurance, resistance, and a combination of endurance-resistance training programs for 5 weeks. Over the training period, functional recovery was monitored weekly using the Sciatic Functional Index (SFI) and histological and morphometric nerve analyses were used to assess the nerve regeneration at the end of the trainings.

RESULTS

The SFI values of the endurance-trained group reached the control values from the first posttraining week and were significantly better than both the resistance-trained group at the first, second, and third posttraining weeks and the concurrent training group at the first posttraining week. At the distal portion of the regenerating sciatic nerve, the endurance-trained group showed a greater degree of the myelinated fiber maturation than the sedentary, resistance-trained, and concurrent training groups. Furthermore, the endurance-trained group showed a smaller percentage area of endoneurial connective tissue and a greater percentage area of myelinated fibers than the sedentary group.

CONCLUSION

These data provide evidence that endurance training improves sciatic nerve regeneration after an experimental traumatic injury and that resistance training or the combination of 2 strategies may delay functional recovery and do not alter sciatic nerve fiber regeneration.

An ultrastructural study of cell death in the CA1 pyramidal field of the hippocapmus in rats submitted to transient global ischemia followed by reperfusion

In the course of ischemia and reperfusion a disruption of release and uptake of excitatory neurotransmitters occurs. This excitotoxicity triggers delayed cell death, a process closely related to mitochondrial physiology and one that shows both apoptotic and necrotic features. The aim of the present study was to use electron microscopy to characterize the cell death of pyramidal cells from the CA1 field of the hippocampus after 10 min of transient global ischemia followed by short reperfusion periods. For this study 25 adult male Wistar rats were used, divided into six groups: 10 min of ischemia, 3, 6, 12 and 24 h of reperfusion and an untouched group. Transient forebrain ischemia was produced using the 4-vessel occlusion method. The pyramidal cells of the CA1 field from rat hippocampus submitted to ischemia exhibited intracellular alterations consistent with a process of degeneration, with varied intensities according to the reperfusion period and bearing both apoptotic and necrotic features. Gradual neuronal and glial modifications allowed for the classification of the degenerative process into three stages: initial, intermediate and final were found. With 3 and 6 h of reperfusion, slight and moderate morphological alterations were seen, such as organelle and cytoplasm edema. Within 12 h of reperfusion, there was an apparent recovery and more 'intact' cells could be identified, while 24 h after the event neuronal damage was more severe and cells with disrupted membranes and cell debris were identified. Necrotic-like neurons were found together with some apoptotic bodies with 24 h of reperfusion. Present results support the view that cell death in the CA1 field of rat hippocampus submitted to 10 min of global transient ischemia and early reperfusion times includes both apoptotic and necrotic features, a process referred to as parapoptosis.

Capsaicin-induced avoidance behavior in the terrestrial Gastropoda Megalobulimus abbreviatus: Evidence for TRPV-1 signaling and opioid modulation in response to chemical noxious stimuli

The aim of this study was to measure the nociceptive response (avoidance latency) of the land snail Megalobulimus abbreviatus (N=8 in each group) after topical capsaicin exposure (0.1% and 0.5% in 20% ethanol) and to compare it to a well-studied stressful (50 degrees C) thermal stimulus model. We also tested if ruthenium red, and capsazepine, respectively nonselective and selective TRPV1 receptor antagonists, could modify both capsaicin- and thermal-evoked responses. Finally, animals were pretreated with morphine, naloxone or morphine plus naloxone prior to capsaicin stimuli. Latencies were measured when the animal lifted its head-foot complex 1 cm from the substrate. Data were compared using ANOVA and LSD post hoc, and the Student T Test (p<0.05). Capsaicin elicited dose-dependent withdrawal behavior. The capsaicin vehicle (20% ethanol) also evoked a less intense but significant avoidance reaction. Capsazepine and ruthenium red attenuated both capsaicin and heat withdrawal responses, when compared to vehicles. Morphine increased, and naloxone, either alone or in combination with morphine, reduced capsaicin-evoked latencies when compared to morphine or saline. These results indicate that the TRPV1 receptor plays a role in the nociceptive circuits of M. abbreviatus.

Dendritic spines in the posterodorsal medial amygdala after restraint stress and ageing in rats

Several evidences suggest that the posterodorsal medial amygdala (MePD) can be a relevant part of the rat neural circuitry for the regulation of hypothalamic neuroendocrine secretion and for ontogenetically different behavioral displays. The dendritic spine density of Golgi-impregnated neurons from the MePD was evaluated in young rats following acute or chronic restraint stress and in aged animals (24 months old). Compared to the control group, a single 1 h restraint stress session promoted a decreased spine density (p<0.01) whereas a single 6 h restraint stress session or daily 6-h restraint sessions for 28 consecutive days did not lead to the same effect (p>0.05). Aged rats showed no difference in this dendritic spine parameter when compared to young adults (p>0.05). These results indicate that short-term stress (1 h) can affect MePD dendritic spines and that neural plasticity is involved with adaptive responses onwards in restrained rats. On the other hand, brain structural modifications related with ageing appear not to influence the number of certain postsynaptic sites in the MePD of rats.

Neuronal somatic volume of posteroventral medial amygdala cells from males and across the estrous cycle of female rats

The posteroventral medial amygdala (MePV) is a brain area where gonadal hormones have neurotrophic effects in rats. The aim of the present study was to estimate the MePV neuronal somatic volume from males and diestrus, proestrus and estrus female Wistar rats (n=5 in each group) in an attempt to identify a possible sexual dimorphism in this parameter. The effect of laterality was also evaluated. The brains of adult animals were sectioned (1 microm), stained with 1% toluidine blue and serial-section reconstructions of each neuronal cell body were obtained. Images from both left and right MePV were studied and the somatic volume was estimated using the Cavalieri method in combination with the point counting technique. Results were compared according to sex and phase of the estrous cycle using a two-way ANOVA for repeated measures followed by the least significance difference test. Mean neuronal somatic volume showed a statistical difference among groups and the post hoc comparisons revealed that males present higher values than females in proestrus and estrus (p<0.05). On the other hand, neither a laterality effect (p=0.6) nor an interaction between groups and laterality (p=0.4) were found. Our results indicate that cell body volume in the MePV is distinct when comparing males to females in the different phases of the estrous cycle. Through dynamic changes modulated by sex steroids, it is likely that this morphological plasticity within the MePV may be affecting the functioning of local neurons and their integrated roles in neural circuits relevant for neuroendocrine control and reproductive behaviors.

Gonadal hormone regulation of glial fibrillary acidic protein immunoreactivity in the medial amygdala subnuclei across the estrous cycle and in castrated and treated female rats

The medial amygdala (MeA) is a sexually dimorphic area that modulates neuroendocrine and behavioral activities and where gonadal hormones play an important role in neuron-glial and synaptic plasticity. Immunohistochemistry was used to identify the astrocytic marker glial fibrillary acidic protein (GFAP) in the different MeA subnuclei--anterodorsal (MeAD), posterodorsal (MePD) and posteroventral (MePV)--of intact female rats in the different phases of the estrous cycle and in ovariectomized females treated with hormonal substitutive therapy. Data semi-quantified by optical densitometry showed that, in the proestrus phase, the GFAP immunoreactivity (GFAP-ir) was higher when compared to the other phases of the estrous cycle (P < 0.02). GFAP-ir was also higher in the MePD than in the MeAD or in the MePV (P < 0. 02). In ovariectomized females, injections of estradiol alone or estradiol plus progesterone increased GFAP-ir in the MePD and in the MePV (P < 0.001), but not in the MeAD (P > 0.3), when compared to control data. These findings suggest that astrocytic GFAP in the MeA subnuclei can be affected either by physiological levels or by hormonal manipulation of the ovarian steroids, which may contribute to the plasticity of local and integrated functional activities of these brain areas in female rats.

Influence of sex and estrous cycle, but not laterality, on the neuronal somatic volume of the posterodorsal medial amygdala of rats

The aim of the present study was to measure the cell body volume of neurons from the posterodorsal subnucleus of the medial amygdala (MePD) of adult male (n=5) and diestrus, proestrus and estrus female (n=4-5 in each group) rats to reveal a possible sexual dimorphism, estrous cycle variations and laterality in this morphological parameter. The brains of adult Wistar rats were sectioned (1 microm), stained with 1% toluidine blue and the stereological estimation of neuronal soma volume of both sides of MePD was realized using the Cavalieri method and the technique of point counting. Data were compared by a two-way ANOVA for repeated measures and the least significance difference post hoc test. In the MePD, mean neuronal somatic volume showed a statistical difference among groups (p=0.005), but neither an effect of laterality (p=0.33) nor interactions between groups and laterality (p=0.78) were found. Post hoc test showed that males (mean+/-S.E.M., 2075.67+/-135.79 microm(3)) have larger mean neuronal somatic volume compared to females in proestrus (1503.30+/-44.46 microm(3)) and in estrus (1616.69+/-71.49 microm(3), p<0.05 in both cases), but not in diestrus (1940.78+/-129.68 microm(3), p>0.05). Moreover, diestrus females displayed larger mean neuronal somatic volume than proestrus female rats (p<0.05). It is suggested that neuronal somatic volume is another sexually dimorphic finding in the MePD, for which it is relevant to set apart the different phases of the estrous cycle to reveal the presence of gonadal hormones effects in the rat MePD neurons.

Effects of daily environmental enrichment on memory deficits and brain injury following neonatal hypoxia-ischemia in the rat

Environmental enrichment (EE) results in improved learning and spatial memory, as well as attenuates morphological changes resulting from cerebral ischemia in adult animals. This study examined the effects of daily EE on memory deficits in the water maze and cerebral damage, assessed in the hippocampus and cerebral cortex, caused by neonatal hypoxia-ischemia. Male Wistar rats in the 7th postnatal day were submitted to the Levine-Rice model of neonatal hypoxia-ischemia (HI), comprising permanent occlusion of the right common carotid artery and a period of hypoxia (90 min, 8%O(2)-92%N(2)). Starting two weeks after the HI event, animals were stimulated by the enriched environment (1h/day for 9 weeks); subsequent to the stimulation, performance of animals in the water maze was assessed. HI resulted in spatial reference and working memory impairments that were completely reversed by EE. Following the behavioral study, animals were killed and the hippocampal volume and cortical area were estimated. There was a significant reduction of both hippocampal volume and cortical area, ipsilateral to arterial occlusion, in HI animals; environmental stimulation had no effect on these morphological measurements. Presented data indicate that stimulation by the daily environmental enrichment recovers spatial memory deficits caused by neonatal hypoxia-ischemia without affecting tissue atrophy in either hippocampus or cortex.

An ultrastructural analysis of cellular death in the CA1 field in the rat hippocampus after transient forebrain ischemia followed by 2, 4 and 10 days of reperfusion

An ultrastructural study was performed to investigate the type of cellular death that occurs in hippocampal CA1 field pyramidal neurons after 10 and 20 min of transient cerebral ischemia in the male adult Wistar rats, followed by 2, 4 and 10 days of reperfusion. The four-vessel occlusion method was used to induce ischemic insult for either 10 or 20 min, following which the animals were submitted to either 2, 4 or 10 days of reperfusion. The animals were then anaesthetised, and their brains removed, dehydrated, embedded, sectioned and examined under a transmission electron microscope. After ischemic insult, neurons from the CA1 field presented alterations, corresponding to the initial, intermediate and final stages of the degenerative process. The only difference observed between the 10 and 20 min ischemic groups was the degree of damage; the reaction was stronger in 20 min groups than in the 10 min groups. While neurons were found in the different stages of oncotic necrosis in all groups, differences were found between the groups in relation to prevalent stages. In both ischemic groups, after 2 days of reperfusion, the initial stage of oncotic necrosis was prevalent and large numbers of neurons appeared normal. In both groups, after 4 days of reperfusion, most of the neurons showed more advanced alterations, typical of an intermediate stage. In both groups, after 10 days of reperfusion, alterations corresponding to the intermediate and final stages of oncotic necrosis were also predominant. However, few intact neurons were identified and the neuropile appeared more organised, with numerous glial cells. In summary, the pyramidal neurons of the CA1 field displayed selective vulnerability and exhibited a morphological death pattern corresponding exclusively to an oncotic necrotic pathway.

Ultrastructural features of neurons and synaptic contacts in the posterodorsal medial amygdala of adult male rats

The aim of the present study was to describe the ultrastructure of neurons (from eight animals) and to analyse the synaptic terminal distribution (from two animals) in the posterodorsal subnucleus of the medial amygdala (MePD) of adult male rats. Using transmission electron microscopy, it was possible to identify many spiny and aspiny dendrites, unmyelinated axonal bundles, single axonal processes, a few myelinated axons, blood vessels and glial processes in the neuropil. Axodendritic synapses were the most frequently observed (67.5%), appearing to be of either the inhibitory or the excitatory types. The presynaptic region contained round or flattened vesicles that occurred either singly or with dense-cored vesicles (DCVs). The dendrites often received many synapses on a single shaft, and axon terminals displayed synaptic contacts with one or more postsynaptic structures. Dendritic spines showed different morphologies and the synapses on them (23.1%) formed a single and apparently excitatory synaptic contact with round, electron-lucid vesicles alone or, less frequently, with DCVs. Inhibitory and excitatory axosomatic synapses (8.2%) and excitatory axoaxonic synapses (1.2%) were also identified. The present report provides new findings relevant to the study of the MePD cellular organization and could be combined with other morphological data in order to reveal the functional activity of this area in male rats.

Permeability of the haemolymph-neural interface in the terrestrial snail Megalobulimus abbreviatus (Gastropoda, Pulmonata): an ultrastructural approach

The aim of this study was to investigate the ultrastructure of the interface zone between the nervous tissue and the connective vascular sheath that surround the central ganglia of the terrestrial snail of Megalobulimus abbreviatus and test its permeability using lanthanum as an electron dense tracer. To this purpose, ganglia from a group of snails were fixed by immersion in a 2% colloidal lanthanum solution, and a second group of animals was injected in the foot with either a 2%, 10% or 20% lanthanum nitrate solution and then sacrificed 2 or 24 h after injection. Ganglia from both groups were processed for transmission electron microscopy. The vascular endothelium, connective tissue and basal lamina of variable thickness that ensheathe the nervous tissue and glial cells of the nervous tissue constitute the interface zone between the haemolymph and the neurones. The injected lanthanum reached the connective tissue of the perineural capsule; however, it did not permeate into the nervous tissue because the basal lamina interposed between both tissues interrupted this passage. Moreover, the ganglia fixed with colloidal lanthanum showed electron dense precipitates between the glial processes in the area adjacent to the basal lamina. It can be concluded from these findings that, of the different components of the haemolymph-neuronal interface, only the basal lamina, between the perineural capsule and the nervous tissue, limits the traffic of substances to and from the central nervous system of this snail.

Further studies on the rat posterodorsal medial amygdala: Dendritic spine density and effect of 8-OH-DPAT microinjection on male sexual behavior

The rat posterodorsal medial amygdala (MePD) is a component of the neural network that modulates male sexual behavior. Dendritic spines were counted in Golgi-impregnated bitufted and stellate neurons and from cells located in the medial and lateral MePD subregions. It was also studied the effect of 8-OH-DPAT, a 5-HT1A receptor agonist, microinjected into the MePD on male sexual behavior. There were no significant differences in the dendritic spine density obtained from multipolar bitufted and stellate neurons (n = 48 cells in each group; p > 0.05) or in the data from the medial or the lateral MePD (n = 48 neurons per region; p > 0.05). Rats were stereotaxically microinjected into the MePD with saline (0.2 microl, n = 6) or 8-OH-DPAT (0.1 and 1.0 microg/0.2 microl, n = 6 and 5, respectively). Behavioral recordings prior to surgery and "non-target" microinjections served as additional control data. 8-OH-DPAT 1.0 microg decreased the latencies to intromission and ejaculation, the postejaculatory refractory period and the mount frequency when compared to control pre-surgery data (p < 0.05). When compared among groups, 8-OH-DPAT 1.0 microg promoted the highest percentage reduction in the postejaculatory refractory period. Saline and injections in the vicinity of MePD did not promote relevant effects on ejaculation (p > 0.05). Results indicate that a similar dendritic spine density can be found in morphologically different populations of MePD neurons and, 8-OH-DPAT can facilitate male sexual behavior by acting on postsynaptic 5-HT1A receptors in this brain area.

Early handling, but not maternal separation, decreases emotional responses in two paradigms of fear without changes in mesolimbic dopamine

This study aimed at identifying the effects of neonatal handling (H) and maternal separation (MS) on two paradigms of fear, learned and innate, and on the tyrosine hydroxylase (TH) immunoreactive cells in adult life. Wistar rats were daily handled with a brief maternal separation, maternal separated for 3 h or left undisturbed during the first 10 days of life. Behavioural responses in the open-field (innate fear) and conditioned fear (learned fear) were evaluated. Moreover, a semi-quantitative analysis of TH immunoreactivity in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNpc) was performed using optical densitometry and confirmed by planar measurements of neuronal density. Early handling decreased behaviour responses of innate and learned fear in adult life, while maternal separation had no significant long-lasting effect on these responses compared to the non-handled group. The behavioural effects of early handling could not be explained by changes in the density of midbrain dopaminergic cells, which were not affected by handling or maternal separation.

A simple and fast densitometric method for the analysis of tyrosine hydroxylase immunoreactivity in the substantia nigra pars compacta and in the ventral tegmental area

Parkinson's disease is a progressive dyskinetic disorder caused by degeneration of mesencephalic dopaminergic neurons in the substantia nigra pars compacta (SNpc) and, to a lesser extent, in the ventral tegmental area (VTA). Tyrosine hydroxylase (TH) is a rate-limiting enzyme for dopamine synthesis, therefore immunohistochemistry for TH can be used as an important marker of dopaminergic cell loss in these regions. Traditionally, immunohistochemical experiments are analyzed qualitatively by optical microscopic observation or more rarely semi-quantitatively evaluated by densitometry. A common problem with such papers is the lack of a clear explanation of the algorithms and macros employed in the semi-quantitative approaches. In this paper, we describe, in detail, an easy, fast and precise protocol for the analysis of TH immunoreactivity in SNpc and VTA using one of the most popular image analysis software packages (Image Pro-Plus). We believe that this protocol will facilitate the evaluation of mesencephalic TH immunoreactivity in various available animal models of Parkinson's disease.

Chronic bilateral common carotid artery occlusion: a model for ocular ischemic syndrome in the rat

BACKGROUND

Ocular ischemic syndrome is a devastating eye disease caused by severe carotid artery stenosis. The reduction of blood flow produced by bilateral common carotid artery occlusion (BCCAO) of rats for 7 days induces events related to gliosis with no evident histological damage. However, retinal degeneration and cellular death occur after 90 days of BCCAO. Our purpose has been to investigate the effects of BCCAO for 30 days in the retina of adult rats.

METHODS

Adult Wistar rats were submitted to BCCAO or sham surgery. Both direct and consensual pupillary light reflexes were investigated before and after surgery, everyday for the first week and weekly for 30 days. After 1 month, eyes were enucleated and embedded in paraffin. The retinal ganglion cell (RGC) density and thickness of the internal plexiform (IPL), internal nuclear, outer plexiform, and outer nuclear layers were estimated.

RESULTS

Four rats of the BCCAO group (50%) lost the direct pupillary reflex in both eyes, three rats (37%) lost this reflex in one eye, and only one (13%) maintained it in both eyes. RGC density (cells/mm) was diminished in the BCCAO group, and a significant decrease was found in the total retina and IPL thickness; however, no changes were evident in the other layers. BCCAO pupillary-reflex-negative rats presented with a significant decrease in total retinal thickness and retinal ganglion cell density compared with the sham group. Both BCCAO pupillary-reflex-positive) and -negative rats showed a decrease in IPL compared with the sham group.

CONCLUSION

This study demonstrates that BCCAO for 30 days induces functional and morphological damage to the retina with loss of the pupillary reflex and a decrease in IPL thickness and RGC number. We suggest that this protocol might be used as a model for ocular ischemic syndrome in the rat.