Standard operating procedures (SOP) in experimental stroke research: SOP for middle cerebral artery occlusion in the mouse

Abstract

2Thus far, the translation of promising results from preclinical stroke research into effective clinical therapy has not met with success (1). Among the numerous possible reasons for this failure, quality problems in some of the basic research or preclinical studies have to be considered. False-positive results, inflated effect sizes, and marginal reproducibility may have overestimated or even affected the potential of novel stroke therapeutics (2). Systematic reviews have found quantitative evidence that low study quality may have introduced a bias into preclinical stroke research (3,4,5). As opposed to many other causes of the 'translational roadblock', study quality is fully under the control of the researcher, and thus a prime target for improvement. Increasingly, funding bodies and review boards overseeing animal experiments are taking a proactive stance, and demand auditable measures of quality control in preclinical research (6). The Stroke Therapy Academic Industry Roundtable (STAIR) recently updated its recommendations for the evaluation of preclinical data on neuroprotective drugs (7) to include good laboratory practice (GLP) issues (8).Monitoring, auditing, and standard operating procedures (SOPs) are key elements of quality control in randomized clinical trials (RCTs). It has been proposed that experimental stroke research adapt some of the tools used in clinical stroke research. In particular, stroke laboratories should set up and publish their SOPs (e.g., on their institutional websites), and guarantee that their studies adhere to these standards (9). This is all the more important, as a certain portion of their experiments, evaluations, etc. are not performed by professionals, but rather by students in training who are unaware of these issues.A standard operating procedure (SOP) is a set of instructions with the force of a directive covering those features of operations that lend themselves to a definite or standardized procedure without loss of effectiveness. The primary purpose of an SOP in experimental stroke research is to guide and standardize working procedures in order to ensure data reliability and integrity. It is crucial that researchers, students and technicians read and follow Nature Precedings :

SorCS2 facilitates release of endostatin from astrocytes and controls post‐stroke angiogenesis

“…To query the significance of SorCS2 for ischemic stroke, we subjected mice either wild‐type (WT) or genetically deficient for Sorcs2 (KO) to 45 min of transient MCAo, an experimental model commonly used in mice (Dirnagl & Members of the MCAO‐SOP Group, ). In WT brains 3 days after MCAo, immunostaining for neuronal (NeuN) and astrocytic (GFAP) markers revealed severe neuronal cell loss and astrogliosis in the ipsilateral hemisphere (Figure a).…”

“…Filamentous occlusion of the middle cerebral artery was performed as described (Dirnagl & Members of the MCAO‐SOP Group, ). Mice were anaesthetized using 2.5% (vol/vol) isoflurane for induction and 1.5% (vol/vol) isoflurane for maintaining anesthesia in a mixture with 25% O 2 and 75% N 2 O. Cerebral ischemia was induced by introducing a 8–0 silicon‐rubber coated suture (Doccol Corp., Sharon, MA) into the left internal carotid artery and by advancing it to the anterior cerebral artery, thereby occluding the middle cerebral artery.…”

Distal hypoxic stroke: A new mouse model of stroke with high throughput, low variability and a quantifiable functional deficit

“…The commonly used intraluminal filament model of MCAO with 60 minutes of occlusion, causes a large infarct and a behavioral deficit; however in B6 mice variability of up to 40% is considered acceptable, as described in a recently published set of standard operating procedures (Dirnagl and MCAO-SOP, 2009). Much of this variability is caused by variation in the anatomy of the Circle of Willis and the patency of the ipsilateral PComA (Barone et al, 1993; Fujii et al, 1997; Kitagawa et al, 1998; Sheng et al, 1999; Wellons et al, 2000; Yonekura et al, 2004).…”

Membrane attack complex inhibitor CD59a protects against focal cerebral ischemia in mice

“…There was no significant difference of the mean body weight between the different groups. All experiments were performed in a randomized manner by investigators blinded to the groups as described and recommended recently by Dirnagl et al (2009) [25]. …”