A new model of experimental hemispherotomy in young adult Rattus norvegicus: a neural tract tracing and SPECT in vivo study

Author(s):Show less -

Matias, Jr., Ivair ^{[1, 2]} ; Elias, Daoud Hibrahim ^[2] ; Bernardino Garcia, Camila Araujo ^[1] ; Silva, Guilherme Henrique ^[1] ; Mejia, Jorge ^[3] ; Cabral, Francisco Romero ^[3] ; Camargo Miranda, Ana Claudia ^[3] ; da Silva, Sergio Gomes ^{[3, 4]} ; Lopes, Luiza da Silva ^[1] ; Coimbra, Norberto Cysne ^{[2, 5]} ; Machado, Helio Rubens ^{[1, 5]}

Affiliation

^[1] Univ Sao Paulo, Ribeirao Preto Med Sch, Dept Surg & Anat, Lab Pediat Neurosurg & Dev Neuropathol, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Ribeirao Preto Med Sch, Dept Pharmacol, Lab Neuroanat & Neuropsychobiol, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Ribeirao Preto Med Sch, Neuroelectrophysiol Multiuser Ctr, Sao Paulo - Brazil

^[4] Univ Mogi das Cruzes, NPT, Sao Paulo - Brazil

^[5] Univ Sao Paulo, Ribeirao Preto Med Sch, Dept Surg & Anat, Neurobiol Pain & Emot Lab, Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF NEUROSURGERY; v. 130, n. 4, p. 1210-1223, APR 2019.
• Web of Science Citations: 1

Abstract

OBJECTIVE The objective of this study was to describe a new experimental model of hemispherotomy performed on laboratory animals. METHODS Twenty-six male young adult Wistar rats were distributed into two groups (surgery and control). The nonfluo-rescent anterograde neurotracer biotinylated dextran amine (BDA; 10,000 MW) was microinjected into the motor cortex area (M1) according to The Rat Brain in Stereotaxic Coordinates atlas to identify pathways and fibers disconnected after the experimental hemispherectomy. SPECT tomographic images of Tc-99m hexamethylpropyleneamine oxime were obtained to verify perfusion in functioning areas of the disconnected and intact brain. A reproducible and validated surgical procedure is described in detail, including exact measurements and anatomical relationships. An additional 30 rodents (n = 10 rats per group) were divided into naive, sham, and hemispherotomy groups and underwent the rotarod test. RESULTS Cortico-cortical neural pathways were identified crossing the midline and contacting neuronal perikarya in the contralateral brain hemisphere in controls, but not in animals undergoing hemispherotomy. There was an absence of perfusion in the left side of the brain of the animals undergoing hemispherotomy. Motor performance was significantly affected by brain injuries, increasing the number of attempts to maintain balance on the moving cylinder in the rotarod test at 10 and 30 days after the hemispherotomy, with a tendency to minimize the motor performance deficit over time. CONCLUSIONS The present findings show that the technique reproduced neural disconnection with minimal resection of brain parenchyma in young adult rats, thereby duplicating the hemispherotomy procedures in human patients. (AU)

• FAPESP's process: 07/01174-1 - Study of the Involvement of opioid-, serotonergic- and noradrenergic-mechanisms of the pain endogenous inhibitory system in antinociceptive processes induced by oriented escape reactions evoked by chemical stimulation of the merdial hypothalamus
• Grantee: Norberto Cysne Coimbra
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/11855-8 - Study of corpus striatum and ventral mesencephalon endocanabinoid influence on neostriato-nigro-tectal GABAergic pathways during panic reactions of rodents threatened by venomous snakes
• Grantee: Norberto Cysne Coimbra
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/03798-0 - Involvement of opioid and endocanabinoid receptors of the substantia nigra on the activity of Nigro-Tectal GABAergic pathways during defensive behaviour elicited by rodents confronted with venomous snakes
• Grantee: Norberto Cysne Coimbra
• Support Opportunities: Regular Research Grants