Effects of Herbal Bath "HAC" on Functional Recovery and c-Fos Expression in the Ventrolateral Periaqueductal Gray Region after Sciatic Crushed Nerve Injury in Rats

Peripheral nerve injuries are a commonly encountered clinical problem and often result in a chronic pain and severe functional deficits. c-Fos expression is sometimes used as a marker of increased neuronal activity. We have developed herbal bath "HAC" for pain control using the following herbs: Harpagophytum procumbens, Atractylodes japonica, and Corydalis tuber. In the present study, we investigated the effects of herbal bath "HAC" on the recovery rate of the locomotor function and the expression of c-Fos in the ventrolateral periaqueductal gray (vlPAG) region of brain following sciatic crushed nerve injury in rats. Walking track analysis for the evaluation of functional recovery and immunohistochemistry for the c-Fos expression were used for this study. In the present results, characteristic gait change with dropping of the sciatic function index (SFI) was observed and c-Fos expression in the vlPAG was suppressed following sciatic crushed nerve injury in rats. Immersion into herbal bath "HAC" enhanced SFI value and restored c-Fos expression in the vlPAG to the control value. These results suggest that herbal bath "HAC" might activate neurons in the vlPAG, and it facilitates functional recovery from peripheral nerve injury. Here we showed that herbal bath "HAC" could be used as a new therapeutic intervention for pain control and functional recovery from peripheral nerve injury.

Physiological Changes by Herbal Bath in Human Body / 日本温泉気候物理医学会雑誌

One of the methods of external treatment is herbal bathing. We studied the usefulness of herbal bathing by investigating the physiological and biochemical changes that occurred during whole-body herbal bathing.<br>Eleven healthy adult males (36±9 years old) were subjected to two types of bathing, herbal bathing and plain water bathing, at an interval of four or more days at random sequence after giving written informed consents. Physiological and biochemical changes were monitored 10min before bathing, 10min during herbal bathing in the sitting position, and up to 60min after bathing.<br>The results showed that the skin temperature of the face (forehead) and hands decreased at a slower rate, fluctuations of the blood pressure were smaller, and the peripheral vascular resistance decreased more faster in herbal bathing than in plain water bathing. These results suggest that herbal bathing is more effective in maintaining peripheral skin temperature, stimulates peripheral circulations, and suppresses excessive fluctuations of blood pressure better than in plain water bathing. Analysis of the autonomic nervous activity by ECG R-R variability showed that the parasympathetic tone was more predominant in the herbal bathing than in plain water bathing, supporting the result showing a larger relaxing effect in herbal bathing. Although there was no significant difference between herbal bathing and plain water bathing in terms of changes in the total blood volume of the Musculus Trapezius, the increase in the total blood volume of the forehead was greater in herbal bathing than in plain water bathing. These results suggested that the herbal bathing might be able to increase the blood volume of the frontal lobe.<br>These differences of the physiological changes between herbal bathing and plain water bathing indicated that the herbal bathing may stimulate the circulation in the frontal lobe as well as the skeletal muscles. These results supported the health-promoting effects of herbal bathing.