RELEVANCE OF SHAM CONTROL GROUP IN PRECLINICAL ANIMAL STUDIES OF CEREBRAL ISCHEMIA

Candamo-Lourido, M.; Lopez-Arias, E.; Lopez-Amoedo, S.; Correa-Paz, C.; B. Bravo, S.; Bugallo-Casal, A.; del Pozo-Filiu, L.; Perez-Gayol, L.; Palomar-Alonso, N.; Chantada-Vazquez, M. P.; Campos, F.; Perez-Mato, M.

doi:10.1101/2023.12.21.572908

bioRxiv · 10.1101/2023.12.21.572908

RELEVANCE OF SHAM CONTROL GROUP IN PRECLINICAL ANIMAL STUDIES OF CEREBRAL ISCHEMIA

Candamo-Lourido, M.·Lopez-Arias, E.·Lopez-Amoedo, S.·Correa-Paz, C.·B. Bravo, S.·Bugallo-Casal, A.·del Pozo-Filiu, L.·Perez-Gayol, L.·Palomar-Alonso, N.·Chantada-Vazquez, M. P.·Campos, F.·Perez-Mato, M.

View original source ↗Export metadata ↓

Abstract

BackgroundIn experimental animal studies, control sham groups are essential to reduce the influence of the surgical intervention on the analysis. The intraluminal filament procedure is one of the most common models of middle cerebral artery occlusion (MCAO) used in the study of cerebral ischemia. However, in these studies, the sham group has not usually been included in the experimental design because of the assumption that the surgical procedure required to access the middle cerebral artery does not affect brain tissue, or that the results obtained from this group are not relevant. ObjectivesIn this study, we aimed to evaluate the relevance of the sham group by analyzing and comparing the brain protein profile of a sham and an ischemic group subjected to the surgical intraluminal filament occlusion of the middle cerebral artery. Material and MethodsThree randomized experimental groups were tested: control group (healthy animals), sham group, and ischemic group. Twenty-four hours after the interventional procedure, the brain tissue was evaluated by magnetic resonance imaging (MRI). After animal perfusion, the brain is removed for proteomic analysis by liquid chromatography-mass spectrometry (LC-MS/MS) using both a qualitative analysis by data-dependent acquisition (DDA) mode and a quantitative analysis, using a sequential window acquisition of all theoretical mass spectra (SWATH-MS) method on a hybrid quadrupole time-of-flight mass spectrometer. ResultsMRI results showed that only animals subjected to cerebral ischemia had ischemic injury. In the sham group 137 dysregulated proteins were detected compared to the 65 in the ischemic group. Moreover, a comparative study of both protein profiles showed the existence of a pool of 17 that appeared dysregulated in both sham and ischemic animals. These results indicate that the surgical procedure required for intraluminal occlusion of the MCA induce changes on brain protein expression that are not associated with the ischemic lesion. ConclusionThis study highlights the importance of including a sham group in the experimental model design to guarantee that the therapeutic target under study is not affected by the surgical intervention.

Explore related subjects

neuroscience Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Candamo-Lourido, M., Lopez-Arias, E., Lopez-Amoedo, S., Correa-Paz, C., B. Bravo, S., Bugallo-Casal, A., del Pozo-Filiu, L., Perez-Gayol, L., Palomar-Alonso, N., Chantada-Vazquez, M. P., Campos, F., Perez-Mato, M.. 2023-12-23. RELEVANCE OF SHAM CONTROL GROUP IN PRECLINICAL ANIMAL STUDIES OF CEREBRAL ISCHEMIA. https://doi.org/10.1101/2023.12.21.572908

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Isogenic forebrain organoids uncover early neurodevelopmental alterations and imbalances in neuronal function leading to hyperexcitation in Gaucher disease

Gaucher disease is a rare lysosomal storage disorder caused by autosomal recessive mutations in the GBA1 gene, encoding the lysosomal enzyme glucocerebrosidase. Gaucher disease is classified in 3 different subtypes depending on the presence and severity of neurological involvement, with type 2 resulting in fatal early-onset neuropathology and patients exhibiting developmental delays, seizures and early death. Studies investigating disease mechanisms of neuronopathic Gaucher disease are mainly based on animal models and focus predominantly on late neuronal phenotypes. Here, we established healthy control and Gaucher disease patient-derived iPSC lines and engineered them to obtain isogenic control and disease lines. Using these lines, we generated cortical and subpallial brain organoids in which we identified early-onset lipid dysregulation in form of glucosylceramide accumulation, highly elevated glucosylsphingosine, and a later increase in ganglioside levels, recapitulating clinical findings. Furthermore, single-cell transcriptomic profiling uncovered novel phenotypes in both cortical and subpallial forebrain organoids. Subpallial alterations consisted of an early increase in migrating interneurons in subpallial organoids, which upregulated cholesterol metabolism. Cortical alterations showed early upregulation of mitochondrial genes and a downregulation of proliferation, with a subsequent switch from GABAergic to glutamatergic neuron fate with a striking increase in gene expression related to the synaptic assembly. Functional assays demonstrated a marked hyperexcitability of cortical organoids and reduced response to GABA-A receptor blockage in Gaucher disease. Additional 2D neuronal network models confirmed the organoid data and showed that both glutamatergic and GABAergic neurons contribute to the phenotype, with hyperexcitability of Gaucher glutamatergic neurons and incapacity of Gaucher GABAergic neurons to balance the excessive excitation. This alteration represents a clinically significant phenotype as many patients exhibit an excitation/inhibition imbalance leading to treatment-resistant seizures, hastening their decline. In conclusion, our defined human models of Gaucher disease identify novel and clear phenotypes that can be used for drug screening or aid in development of new therapeutic strategies to ameliorate Gaucher disease.

neuroscience↗

bioRxiv2026

Oxytocin and Vasopressin Immunoreactivity Differs Across Auditory Brainstem Nuclei in Rodents with Distinct Social Systems

Oxytocin (OT) and vasopressin (AVP) are neuropeptide hormones involved in regulating animal social behavior and a broad spectrum of physiological processes. Although their distributions are well documented in neuroendocrine regions of the forebrain and midbrain, their expression in the hindbrain remains poorly understood. Here, we used immunohistochemistry to quantify OT and AVP immunoreactive puncta within three auditory brainstem nuclei, the lateral superior olive (LSO), the medial superior olive (MSO), and the medial nucleus of the trapezoid body (MNTB) in six wild-caught rodent species differing in sociality. We also quantified the volume of these nuclei and examined variation in total brain volume across species and sociality. OT and AVP puncta count differed among species and social groups. Group-living species exhibited higher OT and AVP puncta counts than monogamous and solitary species in the LSO and MNTB. In the MSO, OT puncta counts did not differ among social groups, whereas AVP puncta counts were higher in group-living than in monogamous and solitary species. Total brain volume and the volumes of the MNTB and MSO differed among species, but not across social groups, whereas LSO volume did not differ among species or sociality. These findings revealed sociality-related variation in OT and AVP immunoreactive puncta within auditory brainstem circuits and suggest that neuropeptide signaling within early auditory brainstem pathways may contribute to the neural integration of social and auditory information.

neuroscience↗

bioRxiv2026

Connexin 40 deficiency alters the temporal profile of postictal oxygen dynamics following focal seizures.

Epilepsy is increasingly recognized as a disorder involving both neuronal and vascular dysfunction. While connexin signaling has been implicated in epileptogenesis, the contribution of vascular connexins to seizure associated cerebrovascular pathology remains poorly understood. Connexin40 (Cx40) is an endothelial gap junction protein that plays a crucial role in vascular communication and blood-flow regulation. Seizures induce dynamic changes in cerebral perfusion and oxygenation, including prolonged postictal hypoperfusion/hypoxia. To determine whether Cx40 influences postictal hypoxia following focal seizures, we examined seizure characteristics and postictal oxygen dynamics in Cx40 knockout (Cx40-/-) mice using an established focal hippocampal seizure model. Electrically kindled seizures were elicited in wild-type and Cx40-/- mice, and local hippocampal tissue oxygenation was continuously monitored before and after seizure induction. Seizure duration did not differ between genotypes, indicating comparable seizure severity. Interestingly, Cx40 deletion altered the temporal pattern of postictal oxygen recovery, producing greater early hypoxia and a delayed secondary rebound in pO2 despite similar peak oxygen levels and overall hypoxic burden. These findings demonstrate that loss of Cx40 selectively alters the temporal profile of postictal oxygen dynamics without affecting seizure duration. Taken together, the results suggest that endothelial gap junctional communication contributes to postictal vascular recovery and identify Cx40 as a potential modulator of seizure associated neurovascular dysfunction.

neuroscience↗