Contents lists available at ScienceDirect Behavioural Brain Research journal homepage: www.elsevier.com/locate/bbr Research report Applicability of the grip strength and automated von Frey tactile sensitivity tests in the mouse photothrombotic model of stroke Faisal F. Alamri a , Abdullah Al Shoyaib a , Abbie Biggers a , Srinidhi Jayaraman a , Josée Guindon b , Vardan T. Karamyan a,c, ⁎ a Department of Pharmaceutical Sciences, School of Pharmacy, TTUHSC, United States b Department of Pharmacology and Neuroscience, School of Medicine, TTUHSC, United States c Center for Blood Brain Barrier Research, School of Pharmacy, TTUHSC, United States ARTICLE INFO Keywords: Photothrombosis Stroke recovery Sensorimotor test Mechanical sensitivity Digital electronic von Frey Anesthesiometer ABSTRACT Improvement of impaired neurological function(s) is a primary endpoint in experimental stroke recovery studies, making the choice and nature of the functional tests crucial for proper execution and interpretation of such studies. Currently, there are a limited number of neurological tests which reliably evaluate functional deficit in mice over a long period of time after stroke. In this study, we evaluated the applicability of forepaw grip strength and automated von Frey tactile sensitivity tests to assess forelimb dysfunction in mice following photo- thrombosis in the sensorimotor cortex, and compared them with two well-established tests, grid-walking and cylinder, for up to 21 days after stroke. Our results indicate that the length of time required to conduct the two new tests is comparable to that of the grid-walking and cylinder tests, however the data from the new tests is obtained and ready for analysis upon completion of the testing session. In addition, our observations indicate that the automated von Frey test detected substantial and sustained deficit in the withdrawal threshold of the mice on all evaluation days after stroke, whereas the forepaw grip strength test was only marginally sensitive to document functional impairment. Our data demonstrate that the automated von Frey tactile sensitivity test is a time efficient and sensitive method which can be used together with other established tests to evaluate long-term functional outcome in the mouse photothrombotic stroke model. 1. Introduction Stroke is a chronically disabling and progressive disease constituting the leading cause of adult disability. Improvement of functional re- covery in disabled stroke survivors is a greatly important but currently unmet therapeutic modality, requiring both pre-clinical and clinical studies to identify safe and effective therapies. Improvement of im- paired neurological function(s) is the primary endpoint in experimental and proof-of-concept therapeutic preclinical stroke recovery studies, making the choice and nature of the functional tests crucial for proper execution and interpretation of such studies. Numerous tests have been developed to assess neurological deficit and outcome in animal stroke models by evaluating motor, somatosensory, cognitive or other func- tions [1–6]. Notably, not all tests are suitable for every stroke model because different stroke models mimic different clinical forms of stroke and therefore result in different neurologic dysfunctions [5,7]. In ad- dition, while mice have become the primary experimental animal in stroke research and many functional tests have been adapted from the rat, testing methods and principles vary between these two species and make comparison of the test results challenging [3,4]. Two of the main mouse ischemic stroke models used in experi- mental recovery studies are the photothrombotic and the endothelin-1 models [8–10], of which the former model primarily results in per- manent interruption of the blood flow in the target area of the brain, whereas in the latter model there is a reperfusion component following the ischemia. Both models have been central in various studies focusing on understanding of the basic biology of the brain recovery following stroke [8,11–17], identification and validation of key molecular targets involved in post-stroke recovery [18,19] and testing of various ther- apeutic approaches for stroke recovery [20–24]. Two of the main functional tests used to monitor sensorimotor function in these stroke models are the grid-walking (also referred to as foot-fault) and the cylinder (also referred to as spontaneous forelimb use task) tests which have been used by multiple laboratories in recent years. Both tests are very sensitive to track functional impairment weeks to months fol- lowing the stroke injury [18,20,25] and allow assessment of http://dx.doi.org/10.1016/j.bbr.2017.09.008 Received 11 August 2017; Received in revised form 29 August 2017; Accepted 4 September 2017 ⁎ Corresponding author at: Department of Pharmaceutical Sciences and Center for Blood Brain Barrier Research, School of Pharmacy, TTUHSC, 1300 Coulter Street, Amarillo, TX, 79106, United States. E-mail address: vardan.karamyan@ttuhsc.edu (V.T. Karamyan). Behavioural Brain Research 336 (2018) 250–255 Available online 08 September 2017 0166-4328/ © 2017 Elsevier B.V. All rights reserved. MARK