Analgesic Effect of Hippophae rhamnoides Extract in Orofacial Pain in Rats / 치위생과학회지

Hippophae rhamnoides L. (sea buckthorn) is a shrub wood that belongs to the bamboo tree family, and is rich in vitamin C, D, and E; it is referred to as a vitamin tree. It is mainly grown in the high mountains of Europe and Central Asia, and has been widely used in China and Russia as natural medicine. Recent studies have shown that it is effective in the treatment of cancer, liver diseases, cardiovascular diseases, and gastrointestinal diseases. However, results of studies on its effect on the regulation of pain are insufficient. In this study, we investigated the effect of sea buckthorn on the development and control of pain in two facial areas. The experimental animals included 7- to 8-week-old Sprague-Dawley rats (240~260 g). Formalin (5%), which is known as an inflammation inducer, was injected into the vibrissa pad or temporomandibular joints to induce orofacial acute pain. Rubbing or scraping of the region injected with formalin was regarded as a pain index, and the behavioral response was observed for 45 minutes after the injection. Sea buckthorn extract diluted to 150, 300 mg/kg (in 1 ml of distilled water) was orally administered 30 minutes prior to the acute pain. The facial pain behavior was effectively reduced in the 300 mg/kg group when compared to the control group (vehicle). Likewise, in an experiment in which formalin was injected into the temporomandibular joints, effective pain alleviation was confirmed at the same drug concentration. These results suggest that sea buckthorn extract may be useful in the development of therapeutic agents for acute inflammatory pain in the orofacial area and for controlling temporomandibular joint pain.

Effects of Red or Black Ginseng Extract in a Rat Model of Inflammatory Temporomandibular Joint Pain / 치위생과학회지

Temporomandibular joint (TMJ) pain is characterized by persistent jaw pain associated with dysfunction and tenderness of the temporomandibular muscles and joints. The aim of this study was to investigate whether treatment with red or black ginseng extract helps in the modulation of inflammatory TMJ pain. Male Sprague-Dawley rats weighing 220~260 g were used. The experimental group was subdivided into 4 groups based on the treatment method (n=6, each group): formalin (5%, 30 µl), formalin after distilled water (vehicle), formalin after red or black ginseng extract (per oral, single or repeated, respectively). To induce TMJ pain, 30 µl of formalin was injected into the articular cavity under ether inhalation anesthesia. The number of noxious behavioral responses of scratching the facial region proximal to the injection site was recorded for 9 successive 5-min intervals following formalin injection. Repeated treatment with red or black ginseng extract reduced the nociceptive responses in the second phase (11~45 min). Nuclear factor erythroid 2-related factor 2 (Nrf2) is an oxidative stress-mediated transcription factor. Both ginsengs significantly down-regulated the increased Nrf2 level compared to the vehicle group. In the test for liver and kidney functions, repeated treatment with red or black ginseng was not different compared to the vehicle group. These results indicate that red and black ginseng extract might be promising analgesic agents in the treatment of inflammatory TMJ pain.