Chronic cerebral hypoperfusion and plasticity of the posterior cerebral artery following permanent bilateral common carotid artery occlusion

Vascular dementia (VaD) is a group of heterogeneous diseases with the common feature of cerebral hypoperfusion. To identify key factors contributing to VaD pathophysiology, we performed a detailed comparison of Wistar and Sprague–Dawley (SD) rats subjected to permanent bilateral common carotid artery occlusion (BCCAo). Eight-week old male Wistar and SD rats underwent BCCAo, followed by a reference memory test using a five-radial arm maze with tactile cues. Continuous monitoring of cerebral blood flow (CBF) was performed with a laser Doppler perfusion imaging (LDPI) system. A separate cohort of animals was sacrificed for evaluation of the brain vasculature and white matter damage after BCCAo. We found reference memory impairment in Wistar rats, but not in SD rats. Moreover, our LDPI system revealed that Wistar rats had significant hypoperfusion in the brain region supplied by the posterior cerebral artery (PCA). Furthermore, Wistar rats showed more profound CBF reduction in the forebrain region than did SD rats. Post-mortem analysis of brain vasculature demonstrated greater PCA plasticity at all time points after BCCAo in Wistar rats. Finally, we confirmed white matter rarefaction that was only observed in Wistar rats. Our studies show a comprehensive and dynamic CBF status after BCCAo in Wistar rats in addition to severe PCA dolichoectasia, which correlated well with white matter lesion and memory decline.

Del laboratorio al campo abierto: El uso de protocolos de adaptación y socialización en Rattus Norvegicus / From the lab to the open field: The use of adaptation and socialization protocols with Rattus Norvegicus

El objetivo de este artículo es presentar un protocolo para la adaptación y socialización de sujetos de investigación Rattus norvegicus, cepa Wistar, como parte de un proyecto que busca el entrenamiento de estos animales para la detección de explosivos, tanto en laboratorio como en campo abierto. Se describe el diseño de las habitaciones de los animales, que son distintas de las jaulas-hogar típicas de los bioterios estándar. A continuación, se relaciona la exposición de los animales a diferentes ambientes físicos. Por último, se examina el protocolo de socialización interespecífica de las ratas tanto con humanos como con animales de otras especies.

The goal of this paper is to introduce an adaptation-and-socialization protocol for animal subjects Rattus norvegicus, Wistar strain, into a research project that aims to train these animals to detect explosives, both in laboratory and open field. We describe the design of the home cages, which are different from the vivarium's standard home cages. Next, the exposure of the animals to different physical environments is related. Finally, the inter-specific socialization protocol of the rats with humans and other animals is described.

White Matter Damage and Hippocampal Neurodegeneration Induced by Permanent Bilateral Occlusion of Common Carotid Artery in the Rat: Comparison between Wistar and Sprague-Dawley Strain

In order to reproduce chronic cerebral hypoperfusion as it occurs in human aging and Alzheimer's disease, we introduced permanent, bilateral occlusion of the common carotid arteries (BCCAO) in rats (Farkas et al, 2007). Here, we induced BCCAO in two different rat strains in order to determine whether there was a strain difference in the pathogenic response to BCCAO. Male Wistar and Sprague-Dawley (SD) rats (250-270 g) were subjected to BCCAO for three weeks. Kluver-Barrera and cresyl violet staining were used to evaluate white matter and gray matter damage, respectively. Wistar rats had a considerably higher mortality rate (four of 14 rats) as compared to SD rats (one of 15 rats) following BCCAO. Complete loss of pupillary light reflex occurred in all Wistar rats that survived, but loss of pupillary light reflex did not occur at all in SD rats. Moreover, BCCAO induced marked vacuolation in the optic tract of Wistar rats as compared to SD rats. In contrast, SD rats showed fewer CA1 hippocampal neurons than Wistar rats following BCCAO. These results suggest that the neuropathological process induced by BCCAO takes place in a region-specific pattern that varies according to the strain of rat involved.