The effects of alpha-pinene on inflammatory responses and oxidative stress in the formalin test

• Published in: Brain research bulletin 2023-10, Vol.203, p.110774-110774, Article 110774
• Main Authors: Rahimi, Kaveh, Zalaghi, Mohammad, Shehnizad, Elahe Ggazi, Salari, Ghazal, Baghdezfoli, Fatemeh, Ebrahimifar, Akram
• Format: Article
• Language: English
• Subjects: Alpha-pinene; Formalin test; Oxidative stress; Pro-inflammatory cytokines
• ISSN: 0361-9230; 1873-2747
• DOI: 10.1016/j.brainresbull.2023.110774

Alpha-pinene (α- pinene), an essential oil that falls under the category of monoterpenes, has various advantages. This research delves into the potential benefits of α-pinene in alleviating nociception caused by the formalin test and the molecular mechanisms involved. Alpha-pinene (1, 5, or 10 mg/kg/day, i.p.) was administrated for 7 days before the formalin test. Observations of nociceptive behaviors were made during the formalin test. We examined the levels of TNF-α and IL-1β, as well as the expression of COX-1 in the spinal cord. Additionally, we evaluated the levels of TNF-α, IL-1β, SOD, GSH, CAT, and MDA in the skin of the hind paw that received a formalin injection. The peripheral injection of formalin triggered nociceptive behaviors, which was notably diminished by α-pinene 5 or 10 mg/kg. The biochemical evaluation revealed that α-pinene significantly moderated the evaluation in TNF-α and IL-1β in the spinal cord induced by formalin injection. Additionally, it was found that α-pinene had a decreasing effect on the expression of COX-1 protein in the spinal cord. Also, α-pinene 5 or 10 mg/kg caused a decrease of TNF-α, IL-1β, and MDA and an increase of SOD, GSH, and CAT at the formalin injection site. The study discovered that doses of 5 or 10 mg/ml of α-pinene can effectively relieve nociceptive response in the formalin test. Alpha-pinene pretreatment reduced the presence of pro-inflammatory cytokines. It also improved the oxidative stress condition by enhancing antioxidant factors and reducing oxidant factors. •Alpha-pinene 5 and 10 mg/kg can effectively alleviate pain in the formalin test.•Alpha-pinene decrease pro-inflammatory cytokines at the injection site of formalin.•Alpha-pinene improve the oxidative stress condition at the formalin injection site.•Alpha-pinene pretreatment also reduced TNF-α and IL-1β in the spinal cord.•Alpha-pinene pretreatment reduce the expression of COX-1 in the spinal cord.