scholarly journals Compensatory Hippocampal Neurogenesis in the Absence of Cognitive Impairment Following Experimental Hippocampectomy in Adult Rats

2021 ◽  
Vol 15 ◽  
Author(s):  
Giuliana T. M. Cardoso ◽  
Walace Gomes-Leal ◽  
Edna C. S. Franco ◽  
Antonio Pereira ◽  
Francinaldo L. Gomes ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Wistar Rats ◽  
Focal Epilepsy ◽  
Hippocampal Sclerosis ◽  
Pathological Finding ◽  
Hippocampal Neurogenesis ◽  
Adult Rats ◽  
Post Surgery ◽  
Mature Neurons ◽  
Adult Hippocampus

Temporal lobe epilepsy (TLE) is the commonest type of focal epilepsy in adult humans, and hippocampal sclerosis (HS) is the main pathological finding in this type of epilepsy. In refractory TLE, patients are indicated for unilateral resection of the affected hippocampus by a surgical procedure called hippocampectomy which generally does not cause any cognitive impairment. Once adult hippocampus is a region of endogenous neurogenesis, even in elderly people, we have hypothesized that a compensatory increase in hippocampal neurogenesis might occur in the remaining hippocampus after unilateral hippocampectomy. To test this hypothesis, we performed unilateral hippocampectomy in adult Wistar rats, which were perfused at 15 (G15) and 30 (G30) days post-surgery. Eighteen Wistar rats were randomly distributed in the following experimental groups: control (no surgery, N = 6), G15 (N = 6), and G30 (N = 6). Adjacent cortex and hippocampus of the left hemisphere were completely removed. Behavioral procedures were performed to address possible cognitive impairments. Brains were collected and fixed from animals belonging to all experimental groups. Gross histopathology was performed using thionine staining. Neuroblasts and mature neurons were immunolabeled using anti-doublecortin (DCX) and anti-NeuN antibodies, respectively. Numbers of DCX and NeuN positive cells were quantified for all experimental groups. Animals submitted to hippocampectomy did not present any cognitive impairment as evaluated by eight-arm radial maze behavioral test. The remaining hippocampus presented a higher number of DCX positive cells compared to control (p < 0.001, ANOVA-Tukey) at both G15 and G30. A higher number of NeuN positive cells were present in the granular layer of dentate gyrus at G30 compared to control and G15 (p < 0.001, ANOVA-Tukey). The data suggest that unilateral hippocampectomy induces compensatory neurogenic effect in the contralateral hippocampus. This may underlie the reported absence of significant cognitive impairment and parallels the findings in human patients submitted to unilateral hippocampectomy to treat refractory TLE.

scholarly journals Compensatory hippocampal neurogenesis in the absence of cognitive impairment following experimental hippocampectomy in adult rats

2020 ◽  
Author(s):  
Giuliana T. M. Cardoso ◽  
Walace Gomes-Leal ◽  
Edna C. S. Franco ◽  
Jessica S. Gama ◽  
Francinaldo L. Gomes ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Wistar Rats ◽  
Focal Epilepsy ◽  
Cognitive Impairments ◽  
Hippocampal Neurogenesis ◽  
Adult Rats ◽  
Post Surgery ◽  
Adult Humans ◽  
Mature Neurons ◽  
Adult Hippocampus

AbstractTemporal lobe epilepsy (TLE) is the commonest type of focal epilepsy in adult humans. In refractory TLE, patients are indicated for unilateral resection of the affected hippocampus (hippocampectomy), which generally does not cause any cognitive impairment. Once adult hippocampus is a region of endogenous neurogenesis, we have hypothesized that a compensatory increase in hippocampal neurogenesis might occur in the remaining hippocampus after unilateral hippocampectomy. To test this hypothesis, we performed unilateral hippocampectomy in adult Wistar rats (n=12). Sham animals were not hippocampectomized (n=6). Animals were deeply anesthetized and adjacent cortex and hippocampus of the left hemisphere were completely removed. They were perfused at 15 (G15, n=6) or 30 (G30, n=6) days post-surgery. Behavioral tests were performed to address possible cognitive impairments. We did not find any cognitive impairment in the hippocampectomized animals. Histopathology was performed using thionine staining and mature neurons and migratory neuroblasts were immunolabeled using anti-NeuN and anti-doublecortin (DCX) antibodies, respectively. The remaining hippocampus presented higher numbers of DCX positive cells compared to control (p<0.001) at both G15 and G30. The results suggest increased compensatory adult neurogenesis following experimental unilateral hippocampectomy in adult rats, which may contribute to absence of cognitive impairments.

scholarly journals Targeting anticipatory neurogenesis to maintain cognitive reserve

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 198-199
Author(s):  
Amar Sahay
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Cognitive Decline ◽  
Cognitive Reserve ◽  
Hippocampal Neurogenesis ◽  
Neurogenic Niche ◽  
Memory Interference ◽  
Age Related ◽  
Adult Hippocampus ◽  
Age Related Cognitive Decline

Abstract Memory imprecision is a hallmark of age-related cognitive decline and mild-cognitive impairment (MCI) and is characterized by increased memory interference and decreased stability of memory representations. Evidence from humans, non-human primates and rodents demonstrate reduced hippocampal neurogenesis, excitation-inhibition imbalance and inflexible hippocampal remapping during age-related cognitive decline and MCI. Developing strategies to reverse cognitive decline during aging and Mild Cognitive Impairment necessitates an understanding of molecular, cellular, circuit and network mechanisms that support memory functions of the hippocampus. Over the last decade we have built a multifaceted program grounded in basic neuroscience that is aimed at improving memory in aging and MCI. We have demonstrated how we can Rejuvenate the aged hippocampus by selectively increasing neurogenesis and how we can Re-engineer connectivity of aged inhibitory microcircuits to improve memory precision in aging. Ongoing efforts include strategies to Repairing neurogenic niche fitness by targeting intercellular communication in the aging hippocampus. In today’s talk I will present a fourth approach catalyzed by our discovery of the first transcriptional regulator of neural stem cell expansion in the adult hippocampus. We will present data in support of this claim and convey how this discovery may guide strategies to maintain cognitive reserve embodied in the pool of neural stem cells in the adult hippocampus.

scholarly journals Synaptic Reshaping and Neuronal Outcomes in the Temporal Lobe Epilepsy

2021 ◽  
Vol 22 (8) ◽  
pp. 3860
Author(s):  
Elisa Ren ◽  
Giulia Curia
Keyword(s):  
Animal Models ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Current Knowledge ◽  
Focal Epilepsy ◽  
Ex Vivo ◽  
Hippocampal Sclerosis ◽  
Control Group ◽  
Epileptogenic Zone ◽  
Epileptiform Discharges

Temporal lobe epilepsy (TLE) is one of the most common types of focal epilepsy, characterized by recurrent spontaneous seizures originating in the temporal lobe(s), with mesial TLE (mTLE) as the worst form of TLE, often associated with hippocampal sclerosis. Abnormal epileptiform discharges are the result, among others, of altered cell-to-cell communication in both chemical and electrical transmissions. Current knowledge about the neurobiology of TLE in human patients emerges from pathological studies of biopsy specimens isolated from the epileptogenic zone or, in a few more recent investigations, from living subjects using positron emission tomography (PET). To overcome limitations related to the use of human tissue, animal models are of great help as they allow the selection of homogeneous samples still presenting a more various scenario of the epileptic syndrome, the presence of a comparable control group, and the availability of a greater amount of tissue for in vitro/ex vivo investigations. This review provides an overview of the structural and functional alterations of synaptic connections in the brain of TLE/mTLE patients and animal models.

scholarly journals Brain Insulin-Like Growth Factor-I Directs the Transition from Stem Cells to Mature Neurons During Postnatal/Adult Hippocampal Neurogenesis

Stem Cells ◽  
2016 ◽  
Vol 34 (8) ◽  
pp. 2194-2209 ◽  
Author(s):  
Vanesa Nieto-Estévez ◽  
Carlos O. Oueslati-Morales ◽  
Lingling Li ◽  
James Pickel ◽  
Aixa V. Morales ◽  
...  
Keyword(s):  
Stem Cells ◽  
Growth Factor ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Brain Insulin ◽  
Mature Neurons ◽  
Growth Factor I

Dietary Choline Deprivation Exacerbates Cardiomyopathy in Streptozotocin-Induced Diabetic Adult Rats

Diabetology ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 190-204
Author(s):  
Ahmed Al-Humadi ◽  
Athina Strilakou ◽  
Hussam Al-Humadi ◽  
Rafal Al-Saigh ◽  
Emmanouel Agapitos ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Dietary Intervention ◽  
Myocardial Dysfunction ◽  
Posterior Wall ◽  
Diabetic Rats ◽  
Diabetic Rat ◽  
Myocardial Inflammation ◽  
Standard Diet ◽  
Adult Rats ◽  
Male Wistar Rats

Choline (Ch) is an essential molecule of substantial importance for the optimal development and function of several biological systems. Ch deprivation has been linked with abnormal fat metabolism, insulin resistance, and myocardial dysfunction. The current study provides evidence of an exacerbation of streptozotocin-induced cardiomyopathy in adult diabetic Wistar rats by dietary Ch deprivation through the administration of a Ch-deprived diet (CDD). Twenty-four adult male Wistar rats were randomly separated into four groups: control, diabetic (DM), choline-deprived through choline-deprived diet (CD), and diabetic choline-deprived (DM + CD). After five weeks of dietary intervention, myocardium echocardiographic and histological assessments were performed. Choline-deprived diabetic rats exhibited significantly slower heart rate, significantly higher myocardial ejection velocity and left ventricle wall tension index with a concomitant significant decreased LV posterior wall thickness as compared to diabetic rats fed on a standard diet. Moreover, histopathological evidence demonstrated an exacerbation of myocardial inflammation and fibrosis associated with significant up-regulation of VEGF expression in the diabetic rat myocardium as a result of Ch deprivation. The study’s findings are of particular significance since the examined experimental approach introduces a previously uncharacterised comorbidity simulation with regards to myocardial structure and functional profiling.

scholarly journals The hematobiochemical status of Wistar rat line under the bovine leukemia virus experimental infection

2019 ◽  
Vol 12 (3) ◽  
pp. 382-388
Author(s):  
Ekaterina Sergeevna Krasnikova ◽  
Fayssal Bouchemla ◽  
Alexander Vladimirovich Krasnikov ◽  
Roman Vladimirovich Radionov ◽  
Anastasia Sergeevna Belyakova
Keyword(s):  
Bovine Leukemia Virus ◽  
Wistar Rats ◽  
Blood Platelets ◽  
Leukemia Virus ◽  
Wistar Rat ◽  
Laboratory Model ◽  
Enzyme Linked Immunosorbent Assay ◽  
Endocrine Disorders ◽  
Adult Rats ◽  
Group I

Aim: This study aimed to elucidate the ability of the bovine leukemia virus (BLV) to integrate into cells of heterologous organisms, in particular, Wistar rats, and examine the manifestations of the pathological process that could be seen in them. Materials and Methods: Wistar rats - were divided into three groups. The first group (I) was fed milk of intact cows, the second (II) - milk of BLV-infected cows, and the third (III) - milk of cows, clinically BLV sick. Rats of all groups were divided into two subgroups: In the subgroup "a", there were adult rats, and in the subgroup "b", their offspring were included. At 3, 6, 9, and 12 months from the start of the experiment, the animals' blood of each group was examined by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay for the presence of BLV provirus and specific anti-leukemia antibodies. A general and biochemical blood test was performed; pathological changes in the internal organs were recorded. Results: Using the PCR, the BLV infection was established in all experimental rats, whose immune response was expressed in varying degrees. At the initial stage of the infection, offspring rats were born healthy. The rats of the control groups Ia and Ib were intact to the BLV throughout the experiment. The biochemical blood tests have shown several signs of intoxication, endocrine disorders, and development of malignant processes in the experimental animals. There are also signs of liver, kidney, and myocardial damages, regardless of whether milk is infected or the cows are clinically leukemic. By the time, the experimental rats developed persistent thrombocytosis with an increase in the average volume of the blood platelets, which may be evidence of the leukemia infection by the megakaryocytic type. The most pronounced character of the change was in the offspring generation. Conclusion: Wistar rats can be considered as a suitable laboratory model to study the BLV pathogenesis. Rats are not BLV natural host, however, they developed the pathognomonic BLV infection symptoms when they were fed infected and leukemic cow's milk.

scholarly journals Use of 2-octyl cyanoacrylate adhesive in rat liver induced lesion

2012 ◽  
Vol 27 (9) ◽  
pp. 624-629 ◽  
Author(s):  
Orlando José dos Santos ◽  
Giancarlo de Souza Marques ◽  
Euler Nicolau Sauaia Filho ◽  
Gustavo Medeiros Frota ◽  
Rayan Haquim Pinheiro Santos ◽  
...  
Keyword(s):  
Rat Liver ◽  
Inflammatory Reaction ◽  
Abdominal Cavity ◽  
Healing Process ◽  
Liver Lesion ◽  
Adult Rats ◽  
Catgut Suture ◽  
Post Surgery ◽  
Cyanoacrylate Adhesive ◽  
Significant Difference

PURPOSE: To evaluate the healing process of rat traumatic liver lesion corrected with the use of 2-octyl cyanoacrylate adhesive, compared to the use of biologically absorbable chromed catgut thread suture. METHODS: Thirty mail adult rats were divided into two groups (15 per group) according to the used method for liver lesion correction as follows: adhesive group (AG), and catgut group (CG); each group being divided into three subsets of five animals (7th, 14th, and 21st day), respectively, according to post-surgery evaluation. All animals were submitted to homogeneous lesion applying synthetic bonding to AG and using chromed catgut suture to CG for lesion correction. Macroscopic and microscopic parameters of healing processes were evaluated. RESULTS: Both groups of animals showed excellent abdominal wall healing, with no evidence of infection, and no abdominal cavity peritonitis or abscess. The presence of adherence was observed in both groups with no statistically significant difference. As to macroscopic evaluation, there was statistically significant difference with respect to specific factors of clinical inflammation (ischemic inflammation and giant celular inflammatory reaction) between animals evaluated on the 10th day (ischemic necrosis and giant celular inflammatory reaction) among animals evaluated on the 14th day (A14 versus C14). CONCLUSION: Applying 2-octyl-cyanoacrylate adhesive for correcting rat liver lesion does not change healing process when compared to the use of chromed catgut stitch.

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