Brain tissue microarrays in neurodegenerative diseases: Validation of methodology and immunohistochemical study of growth-associated protein-43 and calretinin

Neural Remodeling of the Left Atrium in Rats by Rosuvastatin Following Acute Myocardial Infarction

Objective

This study aims to investigate the effect of rosuvastatin on sympathetic neural remodeling of the left atrium (LA) in rats after myocardial infarction (MI).

Methods

Rats were randomly divided into a three groups: sham group, statin group, and MI group. The mRNA expression levels of the growth-associated protein-43 (GAP43) and nerve growth factor (NGF) were measured by RT-PCR. Immunohistochemistry was used to detect the distribution and density of GAP43- and NGF-positive nerves. The expression levels of these proteins were quantified by Western blot.

Results

Compared with the sham group, the average optical density (AOD) values of GAP43 and nerve growth factor (NGF)-positive substances in the LA in the statin and MI groups were significantly higher (P<0.01), but the AOD values in the statin group were lower than of those in the MI group (P<0.01). Furthermore, the AOD values of GAP43 and NGF positive nerves in the left stellate ganglion in the statin and MI groups were significantly higher (P<0.01), but the AOD values in the statin group were lower, when compared with the MI group (P<0.01).

Conclusion

Rosuvastatin could effectively improve the sympathetic neural remodeling of LA in MI rats.

Possible role of miR-204 in optic nerve injury through the regulation of GAP-43

Optic nerve injury is a common disease. The present study aimed to examine the possible role of microRNA‑204 (miR‑204) in optic nerve injury through the regulation of growth‑associated protein-43 (GAP‑43). Initially, optic nerve injury models were established in Sprague‑Dawley (SD) rats, and the function of miR‑204 was either enhanced or inhibited through injection of miR‑204 mimic and inhibitor, respectively. Subsequently, the mRNA and protein levels of miR‑204, GAP‑43, toll‑like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and nuclear factor‑κB (NF‑κB) were examined in retinal tissues using reverse transcription‑quantitative polymerase chain reaction and western blot analyses. The apoptosis of retinal tissue cells was also detected using a terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay. There was a significant increase in the level of miR‑204 in retinal blood vessels of the model SD rats, compared with that in the normal SD rats (P<0.05), and the expression of GAP‑43 was significantly decreased (P<0.05). The results confirmed that the expression of GAP‑43 was significantly reduced, compared with that in the normal control group when the rats were treated with miR‑204 mimic (P<0.05), which was similar to the result in the model group. By contrast, its expression of GAP‑43 was significantly increased when treated with the miR‑204 inhibitor (P<0.05). Compared with the normal control group, the expression levels of TLR4, MyD88 and NF‑κB were significantly increased in the miR‑204 mimic group and model group (P<0.05), whereas the same three factors in the miR‑204 inhibitor group were effectively inhibited, compared with those in the model group, and showed similar results to the normal control group. The apoptotic rates of retinal cells in the miR‑204 mimic group and model group were significantly increased, compared with that in the normal control group (P<0.05), whereas miR‑204 inhibitor effectively reversed the effects on apoptotic rate observed in the model group, showing similar results to those in the normal control group. Taken together, miR‑204 promoted the apoptosis of retinal cells through inhibiting GAP‑43, providing theoretical guidance for the function of GAP‑43 in retinal injury.

Hippocampal expression of synaptic structural proteins and phosphorylated cAMP response element-binding protein in a rat model of vascular dementia induced by chronic cerebral hypoperfusion

The present study established a rat model of vascular dementia induced by chronic cerebral hypoperfusion through permanent ligation of bilateral common carotid arteries. At 60 days after modeling, escape latency and swimming path length during hidden-platform acquisition training in Morris water maze significantly increased in the model group. In addition, the number of accurate crossings over the original platform significantly decreased, hippocampal CA1 synaptophysin and growth-associated protein 43 expression significantly decreased, cAMP response element-binding protein expression remained unchanged, and phosphorylated cAMP response element-binding protein expression significantly decreased. Results suggested that abnormal expression of hippocampal synaptic structural protein and cAMP response element-binding protein phosphorylation played a role in cognitive impairment following chronic cerebral hypoperfusion.

Changes induced by natural scrapie in the calretinin-immunopositive cells and fibres of the sheep cerebellar cortex

Calretinin (CR)-immunopositive cells and fibres in the cerebellar cortex (vermal archicerebellum and neocerebellum) of scrapie-affected, ARQ/ARQ, Rasa Aragonesa breed sheep were studied in comparison with healthy, young and aged, ARQ/ARQ, Rasa Aragonesa animals and with Manchega breed sheep. The scrapie-affected sheep showed signs of both cellular involution and hypertrophic/hyperimmunoreactive responses in all neuronal subtypes; the distribution of the neuronal subtypes in the archi- and neocerebellum, however, did not change compared with controls. The results suggest that the different CR expression and/or CR content of cerebellar cortical neurons in scrapie-affected sheep are more related to their specific functions than any neuroprotective response. The reduction in the cell density of some CR-immunopositive neuronal subsets (i.e. unipolar brush cells) is contradictory to the supposed neuroprotective role of the calcium binding protein CR. However, the hyperimmunoreactivity of many CR-immunopositive neuronal subsets (e.g. the Purkinje cells) suggests the involvement of an over-expression of CR (transitory or restricted to selected neurons) as an adaptative mechanism to fight against the neurodegeneration caused by this prion disease. The changes in the number of immunopositive cells and the hypertrophic/hyperimmunoreactive response seen in scrapie-affected and aged sheep suggests that some different and some similar mechanisms are at work in this disease and aging.

High-content analysis in neuroscience

High-content analysis (HCA) combines automated microscopy and automated image analysis to quantify complex cellular anatomy and biochemistry objectively, accurately and quickly. High-content assays that are applicable to neuroscience include those that can quantify various aspects of dendritic trees, protein aggregation, transcription factor translocation, neurotransmitter receptor internalization, neuron and synapse number, cell migration, proliferation and apoptosis. The data that are generated by HCA are rich and multiplexed. HCA thus provides a powerful high-throughput tool for neuroscientists.