RETRACTED: Activation of the P2X7 receptor in the dental pulp tissue contributes to the pain in rats with acute pulpitis

Abstract

Treatment of acute pulpitis (AP) is beneficial for pain relief and pulp regeneration. The purinergic P2X7 receptor activation is responsible for the formation and maintenance of inflammation and pain. This study aims to determine the role of the pulp tissue P2X7 receptor to activate the mechanisms of the AP in rats. The Sprague-Dawley rats were divided into groups, namely, normal, normal saline (NS), and lipopolysaccharide (LPS) groups. Alterations in pain behavior were detected through head-withdrawal thresholds (HWTs), and the pathological changes in pulp tissue were studied through hematoxylin and eosin staining. The expression of the P2X7 receptor in pulp tissue was observed through immunohistochemistry and Western Blotting. The effect of the P2X7 receptor antagonist A-740003 on HWTs was also observed. The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the pulp tissue of rats were analyzed through enzyme-linked immunosorbent assay. The HWTs were reduced in the rats with AP. Inflammation is formed but was found more severe in the LPS group than the NS group, and the expression levels of the P2X7 receptors in the NS and LPS groups were higher than in the normal group. The periodontal ligament injection of the A-740003 dose-dependant increases the HWTs in rats with AP. The IL-6 and TNF-α levels in the pulp in the NS and LPS groups were increased but reversed by A-740003 injection. In rats with AP, the expression level of the P2X7 receptor and IL-6/TNF-α release was upregulated. The A-740003 can relieve pain and reduce the inflammation progression in rats with AP.

Combined Transcriptomic and Proteomic Profiling of the Mouse Anterior Cingulate Cortex Identifies Potential Therapeutic Targets for Pulpitis-Induced Pain

“…Currently, the mechanisms underlying pulpitis-induced pain were primarily at the peripheral level, with limited research on central mechanisms. ,− , While it is known that ACC was activated during pain, − ,, its involvement in pulpitis-induced pain remained unclear. To address these gaps, we conducted transcriptomic and proteomic analyses and verified the key DEGs and DEPs by qRT-PCR in the ACC of pulpitis models.…”

“…Pulpitis is characterized by acute and intense pain and often requires emergency dental care. − Pulpitis often presents with pain without stimulation, frequently accompanied by neurological issues, such as sleeplessness, memory loss, and anxiety-like feelings that negatively impact patients’ quality of life. − Currently, pulp chamber drainage, root canal therapy, and temporary drug relief methods are used to treat pulpitis . Despite significant scientific progress over the past decade, no rapid, specific, and effective pain medication has been developed for pulpitis-induced pain. − Thus, it is imperative to investigate the underlying mechanisms to find effective treatments.…”

“…Despite significant scientific progress over the past decade, no rapid, specific, and effective pain medication has been developed for pulpitis-induced pain. − Thus, it is imperative to investigate the underlying mechanisms to find effective treatments. The mechanism of pulpitis-induced pain has been largely investigated in the peripheral and trigeminal nucleus caudalis, ,− with few reports on other central mechanisms. It has been reported that thalamic projections project upward to other brain regions such as the anterior cingulate cortex (ACC), the insular cortex, and the somatosensory cortex.…”

Involvement of microglial P2X7 receptor in pain modulation

“…Besides its presence in brain cells, P2X7R is also expressed in the salivary gland epithelium, with heightened expressed in patients afflicted with primary desiccation syndrome 46 . Furthermore, P2X7R expression is upregulated in the pulpitis tissue in human and rats 47,48 . On all accounts, P2X7R is a pivotal molecular expressed throughout the body and primarily concentrated on the microglia.…”

“… 46 Furthermore, P2X7R expression is upregulated in the pulpitis tissue in human and rats. 47 , 48 On all accounts, P2X7R is a pivotal molecular expressed throughout the body and primarily concentrated on the microglia.…”