Grip strength meter

The neurological functions were evaluated by the modified neurological severity score (mNSS) and grip strength tests as previously described with minor adjustments [29 (link)]. The mNSS test was conducted on mice 24 h or 72 h after MCAO. The mNSS test evaluates various domains: sensory, motor, reflex, and balance. Scoring for this test ranges from 0 to 12, where higher scores indicate more pronounced neurological impairments. The grip strength test was employed to assess the forelimb muscle strength of the mice. Each mouse’s tail was lifted to force it to grasp the platform of the grip strength meter (Ugo Basile, Gemonio, Italy). Subsequently, the mouse was pulled away from the platform in a linear manner. The maximal grip strength exerted by the forelimbs during this process was documented.

The grip strength was tested by the apparatus of Grip‐strength meter (Ugo basile, Italy) according to the manufacturer's instructions. Briefly, each mouse was held by the tail and lowered toward the dynamometer's triangle and allowed to grasp it with its forepaws, then pulled the mouse steadily by the tail away from the rod until the mouse's grip was broken. The apparatus recorded the peak value of strength. The grip strength of each mouse was tested for three times, each time interval was 5 min, and the maximum value was used as the grip strength score for that mouse.

Muscular strength was assessed using a grip strength measurement apparatus (grip strength meter, Ugo Basile, Italy). Each mouse was allowed to maintain grip on a wire mesh screen with its forelimbs. The tail was gently and steadily pulled to measure the maximum force until the mouse released the wire mesh screen. Grip strength was indicated as gram-force to release the wire mesh screen for each of the three trials. Grip strength was averaged from three consecutive trials.

As a control, grip testing was performed to objectively quantify rat muscular strength. A Grip Strength Meter (Cat #47200; Ugo Basile Srl, Monvalle Varese, Italy) measured the forelimb grip strength for each rat twice on Day 2 to obtain a baseline value and again on Days 31 and 67 (Fig. 1). Briefly, the rats were gently held by their tails before being placed over the top of a grid such that their front paws could grip the strength meter. Rats were then pulled backwards until they could no longer hold onto the meter, thereby measuring their maximal grip strength.

This test is based on the tendency of a rat to instinctively grasp a bar or a grid when suspended by the body, and permits assessment of the strength of the forelimbs. The test apparatus (Grip Strength Meter, Ugo Basile, Italy) consisted of a grasping bar attached to a force transducer in order to measure the maximum force applied by the rat during the pull. The unit of force used was grams-of-force. Each animal was handled via the body and brought near the bar, allowing the grasping of the grid with both forepaws and then gently pulled back until they released it. Animals were trained and tested on two consecutive days, using the same protocol. Five such measurements were obtained for each animal, and the resting period between each pull was 1 min (Jeyasingham et al., 2001 (link); Aartsma-Rus and van Putten, 2014 (link)).