Evaluation of Pain in Acute Pulpitis Hyperalgesia Model Rats

ObjectiveTo establish a rat hyperalgesia model of acute pulpitis induced by lipopoly-saccharide (LPS) administration to the maxillary molars. In addition, to analyze and evaluate the acute pain and LPS-induced pulpitis, and to investigate the change of pain threshold in rats with acute pulpitis.MethodsForty-five adult male Sprague-Dawley (SD) rats were equally divided into LPS group, normal saline (NS) group, and blank control (SHAM) group, with 15 rats in each group. Under isoflurance anesthesia, the rats in the LPS group had their right upper molar teeth drilled and LPS was sealed temporarily with Caviton, while those in the NS group had their right upper molar teeth drilled and normal saline was sealed temporarily with Caviton. Rats in the SHAM group, serving as blank control group,were only anesthetized with isoflurane. Pain behavioral indexes, including spontaneous pain behavior scores, 50% paw withdrawal threshold (PWT), head withdrawal thresholds (HWT), paw withdrawal latency (PWL), and head withdrawal