Tail-Hanging Test" Behavioral Parameter of Vestibular Deficit and Compensation in Labyrinthectomized Mouse Model

Abstract

Purpose: We are introducing a method to quantify the balance function in mouse with unilaterally damaged vestibular organ. The findings of this method were previously described in 1987 and were used to confirm the acute deficient status of rodents with unilateral or bilateral vestibular dysfunction. The method named as Tail-Hanging Test (THT) could be the useful method to test mostly vestibular system by confusing the somatosensory system and obstructing the visual input as like as like as posturography in human study. Materials and Methods: Fifteen mice underwent unilateral labyrinthectomy and five mice of control group underwent sham operation. After the surgery, the tail of mouse was fixed at the experiment stand and spinning motion was recorded at postoperative 24, 72, and 144 hours. In control group, recording was done at 24 hours. The recorded images were processed with the digital-video-based tracking system using image subtraction technique. Several numerical parameters were compared among different postoperative periods and control group. Results: Minimum angle (MA), mean angle changing velocity (MACV) and mean spinning velocity (MSV) showed the equal variance (p < 0.05, Bartlett's test) and study group showed statistically different result from those of control group (p < 0.05, ANOVA), which means that these three parameters can be indicators to distinguish the normal mouse from the mouse with significant vestibular damage. The results about MA and maximum spinning width (MSW) among three different periods showed the statistically significant difference with equal variance (p < 0.05, ANOVA, Bartlett's test), and it suggests two parameters reflects vestibular compensation depending on the elapsed times after the unilateral damage to the vestibular system. Conclusion: We successfully quantified the balance function in animal. It will be helpful & easy to estimate vestibular function and compensation status at laboratory. MA of THT could be used for evaluation of vestibular damage and compensation of it simultaneously.