Comparison of alpha-synuclein immunoreactivity in the spinal cord between the adult and aged beagle dog

The Central Fluid Percussion Brain Injury in a Gyrencephalic Pig Brain: Scalable Diffuse Injury and Tissue Viability for Glial Cell Immunolabeling following Long-Term Refrigerated Storage

Traumatic brain injury (TBI) affects millions of people annually; however, our knowledge of the diffuse pathologies associated with TBI is limited. As diffuse pathologies, including axonal injury and neuroinflammatory changes, are difficult to visualize in the clinical population, animal models are used. In the current study, we used the central fluid percussion injury (CFPI) model in a micro pig to study the potential scalability of these diffuse pathologies in a gyrencephalic brain of a species with inflammatory systems very similar to humans. We found that both axonal injury and microglia activation within the thalamus and corpus callosum are positively correlated with the weight-normalized pressure pulse, while subtle changes in blood gas and mean arterial blood pressure are not. We also found that the majority of tissue generated up to 10 years previously is viable for immunofluorescent labeling after long-term refrigeration storage. This study indicates that a micro pig CFPI model could allow for specific investigations of various degrees of diffuse pathological burdens following TBI.

Immunohistochemical localization of alpha-synuclein in the retina of some nocturnal and diurnal animals

Although alpha-synuclein has been reported to participate in neurodegenerative diseases, the actual normal biological function of alpha-synuclein remains unclear. I investigated the correlation of alpha-synuclein expression with nocturnal and diurnal activity for various species. Hematoxylin and eosin staining, periodic acid-Schiff's reaction (PAS) and immunohistochemistry of alpha-synuclein expression were performed for the retinas of diurnal, nocturnal, nocturnal with diurnal activity species. I found different intensity of alpha-synuclein expression in the retinal layers. I found alpha-synuclein expression in the outer segment of the photoreceptor layer in the diurnal studied species and absence of alpha-synuclein expression in the compartments of photoreceptor layer in the retina of nocturnal species. I found localization of alpha-synuclein in the inner and outer segments of photoreceptors of the retina of nocturnal with diurnal activity species. The retinas of diurnal animals exhibited glycogen in the paraboloid structure in the inner segment of the photoreceptor layer. The retinas of nocturnal and nocturnal with diurnal activity species were devoid of glycogen in the photoreceptor layer. I conclude that the function of alpha-synuclein is more related to diurnal than to nocturnal species.

Molecular and histologic outcomes following spinal cord injury in spiny mice, Acomys cahirinus

The spiny mouse (Acomys cahirinus) appears to be unique among mammals by showing little scarring or fibrosis after skin or muscle injury, but the Acomys response to spinal cord injury (SCI) is unknown. We tested the hypothesis that Acomys would have molecular and immunohistochemical evidence of reduced spinal inflammation and fibrosis following SCI as compared to C57BL/6 mice (Mus), which similar to all mammals studied to date exhibits spinal scarring following SCI. Initial experiments used two pathway-focused RT-PCR gene arrays ("wound healing" and "neurogenesis") to evaluate tissue samples from the C2-C6 spinal cord 3 days after a C3/C4 hemi-crush injury (C3Hc). Based on the gene array results, specific genes were selected for RT-qPCR evaluation using species-specific primers. The results supported our hypothesis by showing increased inflammation and fibrosis related gene expression (Serpine 1, Plau, and Timp1) in Mus as compared to Acomys (p < .05). RT-qPCR also showed enhanced stem cell and axonal guidance related gene expression (Bmp2, GDNF, and Shh) in Acomys compared to Mus (p < .05). Immunohistochemical evaluation of the spinal lesion at 4 weeks postinjury indicated less collagen IV immunostaining in Acomys (p < .05). Glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1(IBA1) immunostaining indicated morphological differences in the appearance of astrocytes and macrophages/microglia in Acomys. Collectively, the molecular and histologic results support the hypothesis that Acomys has reduced spinal inflammation and fibrosis following SCI. We suggest that Acomys may be a useful comparative model to study adaptive responses to SCI.