Intervention effect of Qufeng Gutong Cataplasm on myofascial pain syndrome in rats and its mechanism / 中国中药杂志

This paper aims to investigate the intervention effect of Qufeng Gutong Cataplasm(QFGT) on myofascial pain syndrome(MPS) in rats and to preliminarily explain its mechanism from the perspective of improving muscle inflammation and pain. Male SD rats were divided into 6 groups, namely normal group, model group, positive control drug(Huoxue Zhitong Ointment, HXZT) group, and low, medium, and high-dose QFGT groups(75, 150, and 300 mg·d~(-1)). The rat model of MPS was established by striking combined with centrifugation for 8 weeks, during which QFGT and HXZT were used for corresponding intervention. Standard VonFrey fiber was used to evaluate the mechanical pain threshold, and acetone was used to detect the cold pain threshold. The electrophysiological activity of muscle at trigger point was detected, and the electromuscular analysis of trigger point was performed. CatWalk gait analyzer was used to detect pain-induced gait adaptation changes. The hematoxylin-eosin(HE) staining was used to observe the pathological changes in muscle and skin tissues at the trigger point of rats. Immunohistochemistry was used to detect the expression of capsaicin receptor transient receptor potential vanilloid 1(TRPV1) in muscle tissues and interleukin(IL)-33 in skin tissues at the trigger point. The protein expression levels of TRPV1, protein kinase B(Akt), phosphorylated protein kinase B(p-Akt), IL-1β, and tumor necrosis factor-α(TNF-α) in muscle tissues at the trigger point were detected by Western blot. The results showed that as compared with the model group, the mechanical pain threshold and cold pain threshold of rats in other groups were increased after treatment with QFGT. The spontaneous electromyography(EMG) activity was observed in the model group, but QFGT alleviated the EMG activity in a dose-dependent manner. Gait analysis showed that standing duration, average intensity, swing speed, maximum contact point, maximum contact area, paw print length, paw print width, and paw print area were significantly improved in all QFGT groups. Pathological results showed that the disorder of muscle arrangement at the trigger point was decreased, muscle fiber adhesion and atrophy were reduced, and inflammatory cell infiltration was alleviated after treatment with QFGT. In addition, QFGT and HXZT both inhibited the protein expression of TRPV1, PI3K, Akt, p-Akt, IL-1β, and TNF-α in the muscle tissues of rats with MPS. However, there was no significant difference in the pathological structure and expression of IL-33 in the treated skin as compared with the normal group. The related results have proved that QFGT can inhibit the release of inflammatory factors by inhibiting the TRPV1/PI3K/Akt signaling pathway in the muscle trigger point of rats with MPS and finally attenuate the atrophy and adhesion of local muscles and inflammatory infiltration, thereby relieving the muscle pain of rats with MPS, and local administration has no skin irritation.

Impact of Personal Computer Use on Musculoskeletal Symptoms in Middle and High School Students

BACKGROUND: There are few studies on the musculoskeletal syndromes from PC use in teenagers. This study investigates the prevalence of musculoskeletal symptoms and its risk factors in school age teenagers who spend time using personal computer with the purpose of preventing such condition. METHODS: The field study was conducted from January to March 2001 at seven PC Bangs in Kimchun. Three hundred twelve teenagers participated in the study. A questionnaire survey was done on how many hours of computer use in a day, their posture, and degree and site of musculoskeletal pain. A physician examined the pressure point around the neck and shoulder and measured the angle of neck, height of the elbow, inner angle of the elbow, angle of the wrist, the distance between the eyes and the monitor while using the computer. RESULTS: The average duration of computer use was 48.1 21.8 months. The average time spent on computer per day was 4.9 1.9 hours. The prevalence of myofascial pain syndrome (MPS) was 36.5% at the neck and shoulder. There was a statistically significant relationship between school grade and the prevalence of MPS at the neck and shoulder (P<0.05). Odds ratio of MPS between middle and high school students was 1.67 at the neck and shoulder (95% C.I: 1.02~2.74). The posture of computer use were not related to the musculoskeletal symptoms. However, there was a significant positive relationship between the average height of elbow and the prevalence of MPS at the neck and shoulder (P<0.05). CONCLUSIONS: We found that posture of computer use and average time spent on computer was related to MPS, assuming that MPS could be increased by those factors. In order to prevent teenagers from MPS resulting from prolonged use of computer, it is essential to fit the desk and chair to their body configuration and instruct them to keep proper posture for computer use.

Changes in the Pressure Threshold of Myofascial Trigger Points Following Freezing Cold Air Application

OBJECTIVE: The purpose of this study is to evaluate the effects of cold air application on the pressure threshold of myofascial trigger points. METHOD: The 60 patients with myofascial trigger points in unilateral infraspinatus muscle were divided into 3 groups with equal number and cold air was applied using CRAis (Kyung-won Century, Korea) for 1, 3 and 5 minutes. We examined the changes of pressure threshold in myofascial trigger points before, immediately after and 30 minutes after cold air application. Also we examined the changes of pressure threshold of contralateral infraspinatus muscles. RESULTS: 1) The pressure threshold of trigger point in infraspinatus muscle were increased immediately and 30 minutes after the cold air application as assessed by the pressure algometer (p0.05). 3) There was no significant correlations among the age, the body mass index and the changes of pressure threshold in myofascial trigger points (p>0.05). CONCLUSION: We conclude that the cold air application is a effective method for treatment of myofascial trigger points.

Changes in the Pressure Threshold of Myofascial Trigger Points of the Shoulder Girdle Muscles Following Stretching Exercise

OBJECTIVE: The purpose of this study is to evaluate the effects of a self-stretching exercise on the pressure threshold of myofascial trigger point. METHOD: We examined the changes of pressure threshold in 66 patients with myofascial trigger points before and after a self-stretching exercise of shoulder girdle and also tested the visual analogue scale (VAS) of the subjective pain intensity. The self-stretching exercise of shoulder girdle includes a stretching exercise of four muscles in shoulder girdle simultaneously, including upper trapezius, levator scapulae, infraspinatus, rhomboideus major and minor, which is followed by 1) a sitting position, relaxed, 2) lateral bending of neck to contralateral side, 3) forward and downward stretching of ipsilateral arm with protrusion of scapula and internal rotation of arm maximally to the contralateral foot. Each stretching motion is maintained for 30 seconds. RESULTS: The results of the patients experiencing unilateral or bilateral myofascial neck and shoulder pain showed that the pressure threshold of trigger point increased in response to the self-stretching exercise as assessed by a pressure algometer. Also visual analogue scale (VAS) decreased in response to the self-stretching exercise. CONCLUSION: We conclude that the self-stretching exercise of shoulder girdle is an effective method for the simultaneous stretching of upper trapezius, levator scapulae, infraspinatus, rhomboideus major and minor.