In order to examine the effectiveness of the application of static magnetic field (SMF) on pain relief, we performed a study on rats with adjuvant arthritis (AA). Sixty female Sprague–Dawley (SD) rats (age: 6 weeks, body weight: approximately 160 g) were divided into three groups [SMF-treated AA rats (Group I), non-SMF-treated AA rats (Group II) and control rats (Group III)]. The SD rats were injected in the left hind leg with 0.6 mg/0.05 ml Mycobacterium butyrium to induce AA. The rats were bred for 6 months as chronic pain model. Thereafter, the AA rats were or were not exposed to SMF for 12 weeks. We assessed the changes in the tail surface temperature, locomotor activity, serum inflammatory marker and bone mineral density (BMD) using thermography, a metabolism measuring system and the dual-energy X-ray absorptiometry (DEXA) method, respectively. The tail surface temperature, locomotor activity and femoral BMD of the SMF-exposed AA rats were significantly higher than those of the non-SMF-exposed AA rats, and the serum inflammatory marker was significantly lower. These findings suggest that the pain relief effects are primarily due to the increased blood circulation caused by the rise in the tail surface temperature. Moreover, the pain relief effects increased with activity and BMD of the AA rats.

To examine the mechanism of the preventive effect of tannins on the progression of carbon tetrachloride (CCl4)-induced acute liver injury in rats, sumac gall (SG) extract and gallic acid (GA) were used as substitutes for crude tannins, because SG is a kind of Chinese traditional medicinal herb containing large amounts of various tannins, and GA is one of the major constituents of SG. The protective effect of oral (p.o.) and intraperitoneal (i.p.) administration of each substance on progression of CCl4-induced hepatitis was investigated in rats. Speculating that the superoxide dismutase (SOD)-like activities (O2 radical-scavenging activities) and/or protective effects of these substances on cell membranes might play a key role in the mechanism opposing the progression of CCl4-induced hepatitis, the O2 radical-scavenging activities in liver cells and serum in rats were monitored. Both substances significantly prevented the progression of acute liver injury with both p.o. and i.p. administration. These findings suggest that the mechanism for this prevention might be due mainly to the protective effect of these substances on cell membranes rather than O2 radical-scavenging activities.

To investigate the improvement in peripheral circulation in autonomic disorders, we monitored skin temperature in the tails of rats by thermography before and after the oral administration of boiled water extract of Toki-shigyakuka-gosyuyu-syokyo-to (TSGS-to). Oral administration of this extract elevated the temperature, calculated as the calories of radiant heat in the rat tail 5-10 min after uptake. The temperature elevation remained stable for more than 20 min. Calories were significantly reduced 60 min after uptake and almost returned to initial values 90 min later. Some of the constituent herbs, especially Angelicae radix, Cinnamomi cortex, Evodiae fructus, and Zingiberis rhizoma, appeared to be active in relieving hypothermia.

To examine the effectiveness of the herbal medicine prescription, Shu-Jing-Huo-Xue-Tang (SJHXT), for pain relief, we performed a study using rats with adjuvant arthritis (AA). After injecting the adjuvant, AA rats were maintained for 6 months as a chronic pain model. Starting at 6 months, SJHXT was administered for 12 weeks. We measured the tail skin temperature and locomotor activity of rats using thermography and a metabolism measuring system, respectively, before and after 12 weeks of SJHXT administration. Normal rats were used as controls. Before SJHXT administration, the tail surface temperature and locomotor activity were significantly lower in the AA rats than in the control rats. The tail skin temperature and locomotor activity of SJHXT-treated AA rats were significantly higher than those of the control rats. These findings suggest that the pain relief effects of SJHXT may be primarily due to increased blood circulation.