Protective effect of Chresta martii extract on the zymosan-induced temporomandibular joint arthritis in rats

Objective Chresta martii is broadly used by folk medicine due to its anti-inflammatory effects, but there is a lack of preclinical data on its pharmacological mechanisms. This study investigated the efficacy of Chresta martii ethanolic extract (CEE) in the zymosan-induced temporomandibular joint arthritis (TMJ) and evaluated the possible role of TNF-α, nitric oxide (NO), and heme oxygenase-1 (HO-1). Methods Male Wistar rats (160-220 g) were pre-treated with CEE (100, 200 or 400 mg/kg; v.o) 1 h before zymosan injection (2 mg; i.art). Mechanical hypernociception (g) was assessed 4 h later. The trigeminal ganglion was collected for TNF-α quantification (ELISA), total cell count and myeloperoxidase activity (MPO) were assayed in the synovial lavage 6 h after arthritis induction. Additionally, animals were pre-treated with L-NAME (30 mg/kg; i.p.) or ZnPP-IX (3 mg/kg, s.c.) to assess the involvement of NO and HO-1, respectively. Results CEE 400 mg/kg (v.o) increased (p < 0.05) hypernociception threshold, reduced the cell counts and MPO activity in the synovial lavage, as well as decreased TNF-α levels in the trigeminal ganglion. ZnPP-IX abolished the analgesic effect of CEE, but not L-NAME. Conclusion The anti-inflammatory and antinociceptive effects of CEE depended on the HO-1 pathway integrity and TNF-α suppression.