Development of a behavior model of pain induced by experimental tooth movement in rats

Abstract

The mechanism of orthodontic pain and discomfort is poorly understood partly because of the limited number of animal behavioral models for pain assessment. This study aimed to develop a behavioral model for assessment of tooth-movement pain in rats using directed face-grooming activity. Male Sprague-Dawley rats weighing 200-300 g were used. They were videotaped on days 1, 3, 5, 7, and 14 after experimental tooth movement and their directed face-grooming behavior was evaluated. In addition, we also evaluated behavioral responses to the application of a progressively higher magnitude force and to multiple applications of an equal magnitude force. Finally, the effects of peripherally and systemically administered morphine and of the N-methyl-d-aspartate (NMDA) receptor antagonist, MK-801, on the behavioral responses were evaluated. The results indicated that time spent on directed face-grooming activity increased dramatically after initiating experimental tooth movement. The change concurred with the initial orthodontic pain response. This behavioral change was reproducible and was related to force magnitude. Application of both systemic and peripheral morphine and MK-801 could exert an analgesic effect on this pain model. These results suggest that directed face-grooming behavior can be a reliable measure for tooth-movement pain in rats, which could be widely used in investigating the orthodontic pain mechanism.

Clinical Physiology and Mechanism of Dizocilpine (MK‐801): Electron Transfer, Radicals, Redox Metabolites and Bioactivity

“…In relation to pain control, the mechanism of orthodontic pain is poorly understood 110. By use of a behavioral model, application of both systemic and peripheral MK-801 and morphine exerted an analgesic effect.…”

Effect of lutein on the acute inflammation‐induced c‐Fos expression of rat trigeminal spinal nucleus caudalis and C1 dorsal horn neurons

“…As the directed face‐grooming activity of mouth wiping was the most robust behavioral response and a reproducible and reliable measurement for pain arising from mustard oil injection , in this study we examined whether lutein administration attenuates spontaneous nocifensive behavior in inflamed rat. Therefore, wakefulness rats were monitored for directed mouth‐wiping activity in a transparent plastic cage (30 × 30 × 30 cm).…”

Chemokine ligand 2 in the trigeminal ganglion regulates pain induced by experimental tooth movement

“…19 According to the procedures developed in previous studies, 19 the rats were videotaped for 10 minutes each time, starting at least 15 minutes after placement in the cage. Each animal was videotaped two times at 10-minute intervals.…”

“…[18][19][20] After an intraperitoneal injection of sodium pentobarbital at a dose of 40 mg/kg body weight, 40 g of force 19,20 was applied for 0 hours, 4 hours, 1 day, 3 days, 5 days, and 7 days. Sham-treated rats received the same procedures, but the springs in their mouths were not active.…”

“…Each animal was videotaped two times at 10-minute intervals. 19 Videotaped behavior was analyzed offline by an investigator who was blinded to the information regarding the rats. Each rat was weighed on every interval day, and changes in body weight versus the previous weights were used for statistical analyses.…”