Characterization of four types of tail abnormalities in rats treated prenatally with valproic acid

Valproic acid (VPA) is an anticonvulsant drug used mainly for the treatment of epilepsy, bipolar disorder and schizophrenia. The VPA has been shown to be a potent teratogen that causes birth defects and malformations. Likewise, there are reports that suggest a relationship between the use of VPA during pregnancy and an increased incidence of children with neurological disorders such as autism. In humans, prenatal exposure to VPA produces malformations including dimorphic facial features suggestive of a lesion in the neural tube, as in the case of spina bifida, heart disease, limb defects and craniofacial anomalies as well as genital abnormalities. Herein we describe four tail abnormalities found in rats treated prenatally with valproic acid, which has been used as an animal model for the study of autistic features. These malformations may be associated with neural damage, but further studies are needed in order to correlate each tail abnormality with the kind of neural alterationEl ácido valpróico (AVP) es un fármaco anticonvulsivo usado principalmente para el tratamiento de la epilepsia, trastorno bipolar y esquizofrenia. Se ha demostrado que el AVP es un teratógeno potente que causa defectos de nacimiento y malformaciones. Así mismo, hay informes que sugieren una relación entre el uso de AVP durante el embarazo y un aumento de la incidencia de niños con trastornos neurológicos tales como el espectro autista. En los seres humanos, la exposición prenatal a la AVP produce malformaciones que sugieren un defecto durante el cierre del tubo neural, como es el caso de la espina bífida, enfermedades del corazón, defectos de las extremidades, anomalías craneofaciales, así como anomalías genitales. En el presente trabajo se describen cuatro anormalidades de la cola en ratas tratadas prenatalmente con ácido valpróico. Este tratamiento se ha utilizado como modelo animal para el estudio de rasgos autistas. Estas malformaciones pudieran estar asociadas con algún daño en el sistema nervioso, sin embargo se requieren más estudios para correlacionar cada anormalidad de la cola con el tipo de alteración neura

Microglia Morphological Categorization in a Rat Model of Neuroinflammation by Hierarchical Cluster and Principal Components Analysis

It is known that microglia morphology and function are closely related, but only few studies have objectively described different morphological subtypes. To address this issue, morphological parameters of microglial cells were analyzed in a rat model of aseptic neuroinflammation. After the injection of a single dose of the enzyme neuraminidase (NA) within the lateral ventricle (LV) an acute inflammatory process occurs. Sections from NA-injected animals and sham controls were immunolabeled with the microglial marker IBA1, which highlights ramifications and features of the cell shape. Using images obtained by section scanning, individual microglial cells were sampled from various regions (septofimbrial nucleus, hippocampus and hypothalamus) at different times post-injection (2, 4 and 12 h). Each cell yielded a set of 15 morphological parameters by means of image analysis software. Five initial parameters (including fractal measures) were statistically different in cells from NA-injected rats (most of them IL-1β positive, i.e., M1-state) compared to those from control animals (none of them IL-1β positive, i.e., surveillant state). However, additional multimodal parameters were revealed more suitable for hierarchical cluster analysis (HCA). This method pointed out the classification of microglia population in four clusters. Furthermore, a linear discriminant analysis (LDA) suggested three specific parameters to objectively classify any microglia by a decision tree. In addition, a principal components analysis (PCA) revealed two extra valuable variables that allowed to further classifying microglia in a total of eight sub-clusters or types. The spatio-temporal distribution of these different morphotypes in our rat inflammation model allowed to relate specific morphotypes with microglial activation status and brain location. An objective method for microglia classification based on morphological parameters is proposed.Main pointsMicroglia undergo a quantifiable morphological change upon neuraminidase induced inflammation.Hierarchical cluster and principal components analysis allow morphological classification of microglia.Brain location of microglia is a relevant factor

The adenosine generating enzymes CD39/CD73 control microglial processes ramification in the mouse brain

<div><p>Microglial cells invade the brain as amoeboid precursors and acquire a highly ramified morphology in the postnatal brain. Microglia express all essential purinergic elements such as receptors, nucleoside transporters and ecto-enzymes, including CD39 (NTPDase1) and CD73 (5'-nucleotidase), which sequentially degrade extracellular ATP to adenosine. Here, we show that constitutive deletion of CD39 and CD73 or both caused an inhibition of the microglia ramified phenotype in the brain with a reduction in the length of processes, branching frequency and number of intersections with Sholl spheres. <i>In vitro</i>, unlike wild-type microglia, cd39^-/- and cd73^-/- microglial cells were less complex and did not respond to ATP with the transformation into a more ramified phenotype. In acute brain slices, wild-type microglia retracted approximately 50% of their processes within 15 min after slicing of the brain, and this phenomenon was augmented in cd39^-/- mice; moreover, the elongation of microglial processes towards the source of ATP or towards a laser lesion was observed only in wild-type but not in cd39^-/- microglia. An elevation of extracellular adenosine 1) by the inhibition of adenosine transport with dipyridamole, 2) by application of exogenous adenosine or 3) by degradation of endogenous ATP/ADP with apyrase enhanced spontaneous and ATP-induced ramification of cd39^-/- microglia in acute brain slices and facilitated the transformation of cd39^-/- and cd73^-/- microglia into a ramified process-bearing phenotype <i>in vitro</i>. These data indicate that under normal physiological conditions, CD39 and CD73 nucleotidases together with equilibrative nucleoside transporter 1 (ENT1) control the fate of extracellular adenosine and thereby the ramification of microglial processes.</p></div