Implantation of Miniosmotic Pumps and Delivery of Tract Tracers to Study Brain Reorganization in Pathophysiological Conditions

Abstract

Pharmacological treatment in animal models of cerebral disease imposes the problem of repeated injection protocols that may induce stress in animals and result in impermanent tissue levels of the drug. Additionally, drug delivery to the brain is delicate due to the blood brain barrier (BBB), thus significantly reducing intracerebral concentrations of selective drugs after systemic administration. Therefore, a system that allows both constant drug delivery without peak levels and circumvention of the BBB is in order to achieve sufficiently high intracerebral concentrations of drugs that are impermeable to the BBB. In this context, miniosmotic pumps represent an ideal system for constant drug delivery at a fixed known rate that eludes the problem of daily injection stress in animals and that may also be used for direct brain delivery of drugs. Here, we describe a method for miniosmotic pump implantation and post operatory care that should be given to animals in order to successfully apply this technique. We embed the aforementioned experimental paradigm in standard procedures that are used for studying neuroplasticity within the brain of C57BL6 mice. Thus, we exposed animals to 30 min brain infarct and implanted with miniosmotic pumps connected to the skull via a cannula in order to deliver a pro-plasticity drug. Behavioral testing was done during 30 days of treatment. After removal the animals received injections of anterograde tract tracers to analyze neuronal plasticity in the chronic phase of recovery. Results indicated that neuroprotection by the delivered drug was accompanied with increase in motor fibers crossing the midline of the brain at target structures. The results affirm the value of these techniques for drug administration and brain plasticity studies in modern neuroscience.

Intracerebroventricular administration of L-arginine improves spatial memory acquisition in triple transgenic mice via reduction of oxidative stress and apoptosis

“…Then, a small bent cannula (Alzet®) was slowly lowered stereotactically into the hole and cemented to the skull with Loctite 454 (Alzet®). Once in place, the cannula reaches 2.5 mm in the dorsoventral direction ( Sanchez-Mendoza et al 2016 ).…”

Presynaptic vesicular accumulation is required for antipsychotic efficacy in psychotic-like rats

“…Using a spacer, the cannula depth was altered to 4.5 mm. Before implantation, filled brain infusion assemblies were incubated in sterile SAL overnight for priming (Sanchez-Mendoza et al, 2016).…”

A New Tool for the Analysis of the Effect of Intracerebrally Injected Anti-Amyloid-β Compounds

“…injection is not considered the preferred choice for targeting the brain, as it induces stress in rodents and requires high doses of drugs [23,24]. In this context, mini-osmotic pumps represent an ideal system for studying long-term treatments in the brain, at a fixed known delivery rate that eludes the problem of daily injection stress in animals and overcomes the BBB by direct intracerebroventricular administration [17,18,25,26].…”

“…The tool presented here can be applied to many types of injections such as stereotactic microinjections, intracortical injections and ventricular injections [17,18,25,26,39]. While our analysis is focused on plaque analysis, our method can be used to determine various other immunohistochemical markers, e.g., intracellular neurofibrillary tangles composed of highly phosphorylated forms of the protein tau, or markers related to neuroinflammation, including the astrocyte marker glial fibrillary acidic protein (GFAP), and the microglia marker ionized calcium-binding adaptor molecule-1 (IBA1).…”