Assessment of the effects of ischaemia/ hypoxia on angiogenesis in rat myofascial trigger points using colour Doppler flow imaging

Assessment of the Effects of Sphingosine Kinase 1/Sphingosine-1-Phosphate on Microangiogenesis at Rat Myofascial Trigger Points Using Contrast-Enhanced Ultrasonography

Purpose

Few studies have assessed the effects of sphingosine kinase 1/sphingosine-1-phosphate (SPHK1/S1P) on microangiogenesis at rat myofascial trigger points (MTrPs) using contrast-enhanced ultrasonography (CEUS). This study aimed to address these deficiencies. Here, we investigated the effects of SPHK1/S1P on MTrP microangiogenesis and the value of CEUS in evaluating these effects.

Methods

Forty Sprague‒Dawley rats were subdivided into two groups: control and MTrP groups. MTrPs were established by 8 weeks of the strike procedure combined with eccentric motion and 4 weeks of recovery. All rats were euthanized after having undergone CEUS with an overdose of pentobarbital sodium. MTrP and control tissue samples were removed for haematoxylin and eosin (H&E) staining and transmission electron microscopy (TEM) imaging. The tissue was dehydrated, cleared, and embedded before sectioning. The sections were then incubated overnight at 4°C, and immunohistochemistry was carried out with primary antibodies including rabbit anti-CD31, rabbit anti-SPHK1and rabbit anti-S1PR1.

Results

MTrP rats exhibited spontaneous electrical activity (SEA) and a local twitch response (LTR) during electromyography (EMG) examination. The CEUS time-intensity curves (TICs) showed that the perfusion intensity in the MTrPs and surrounding tissue area was increased, with faster perfusion than in normal sites, while the TICs in the control group slowly increased and then slowly decreased. The correlation coefficient between the microvessel density (MVD) and sphingosine 1-phosphate receptor 1 (S1PR1) was 0.716 (p <0.01). Spearman correlation analysis revealed that Spearman's rho (ρ) values between the MVD and peak intensity (PI), between the MVD and area under the curve (AUC), and between the MVD and SPHK1 were > 0.5 (p <0.05), > 0.7 (p <0.01), and > 0.7 (p <0.01), respectively.

Conclusion

CEUS is valuable for detecting microangiogenesis within MTrPs, and SPHK1/S1P plays an important role in promoting MTrP tissue microangiogenesis.

Assessment of the effects of transforming growth factor beta1 (TGF-β1)-Smad2/3 on fibrosis in rat myofascial trigger points using point shear wave elastography

Background & Aims

Myofascial trigger points (MTrPs) are highly sensitive irritated points within a tense belt of skeletal muscle, and are the main cause of muscle pain and dysfunction. MTrPs can also cause paraesthesia and autonomic nervous dysfunction. Furthermore, long-term and chronic MTrPs can cause muscle atrophy and even disability, seriously affecting the quality of life and mental health of patients, and increasing the social and economic burden. However, to date, there have been few studies on fibrogenesis and changes in MTrPs. Therefore, this study investigated whether transforming growth factor beta1 (TGF-β1)-Smad2/3 participates in the formation of MTrPs and how it affects fibrosis using point shear wave elastography.

Methods

Forty Sprague‒Dawley rats were randomly divided into the MTrPs group and the control group. Blunt injury combined with eccentric exercise was used to establish an MTrPs model. Electromyography (EMG), haematoxylin and eosin (H&E) staining and transmission electron microscopy (TEM) were used to verify the model. The collagen volume fraction was measured by Masson staining, the protein expression of TGF-β1 and p-Smad2/3 was measured by Western blotting (WB) and immunohistochemistry (IHC), and the shear wave velocity (SWV) was measured by point shear wave elastography.

Results

EMG, H&E and TEM examination indicated that the modelling was successful. The collagen volume fraction and the protein expression of TGF-β1 and p-Smad2/3 were higher in the MTrPs group than in the control group. The SWV of the MTrPs group was also higher than that of the control group. These differences suggest that MTrPs may exhibit fibrosis. The correlations between the collagen volume fraction and SWV and between the collagen volume fraction and TGF-β1 were positive.

Conclusion

Fibrotic conditions may be involved in the formation of MTrPs. Ultrasound point shear wave elastography and assessment of TGF-β1 and p-Smad2/3 expression can reflect the degree of MTrPs fibrosis to some extent. Further exploration of the important role of TGF-β1 and Smad2/3 in the pathogenesis of MTrPs will be of great significance for clinical treatment.

Effect of Manual Therapy Compared to Ibuprofen on Primary Dysmenorrhea in Young Women-Concentration Assessment of C-Reactive Protein, Vascular Endothelial Growth Factor, Prostaglandins and Sex Hormones

Background: The study aimed to assess if manual therapy, compared to ibuprofen, impacts the concentration of inflammatory factors, sex hormones, and dysmenorrhea in young women Methods: Thirty-five women, clinically diagnosed with dysmenorrhea, were included in the study. They were divided into group A—manual therapy (n = 20) and group B—ibuprofen therapy (n = 15). Inflammatory factors such as vascular endothelial growth factor (VEGF), C-reactive protein (CRP), prostaglandin F2α (PGF_2α), E2 (PGE2) and sex hormones levels were measured. Dysmenorrhea assessed with the numerical pain rating scale (NPRS), myofascial trigger points, and muscle flexibility were examined before and after the interventions. Results: The difference in the level of 17-β-estradiol after manual and ibuprofen therapy was significant, as compared to baseline (p = 0.036). Progesterone levels decreased in group A (p = 0.002) and B (p = 0.028). The level of CRP was negatively correlated with sex hormones. Decrease in dysmenorrhea was significant in both groups (group A p = 0.016, group B p = 0.028). Non-significant differences were reported in prostaglandins, VEGF and CRP levels, in both groups. Conclusions: There were no significant differences in CRP, prostaglandins and VEGF factors after manual or ibuprofen therapy. It has been shown that both manual therapy and ibuprofen can decrease progesterone levels. Manual therapy had a similar effect on the severity of dysmenorrhea as ibuprofen, but after manual therapy, unlike after ibuprofen, less muscles with dysfunction were detected in patients with primary dysmenorrhea.

Intramuscular stimulation as a new modality to control postthoracotomy pain: A randomized clinical trial

OBJECTIVE

Postoperative pain after thoracic surgery primarily hinders patients' mobility, decreasing the quality of life. To date, various modalities have been suggested to improve postoperative pain. However, pain alleviation still remains a challenge, resulting in continued reliance on opioids. To tackle this problem, this study introduces a needle electrical twitch obtaining intramuscular stimulation (NETOIMS) as a new effective treatment modality for postoperative pain after thoracoscopic surgery.

METHODS

This randomized clinical trial analyzed patients receiving video-assisted thoracoscopic surgery pulmonary resection between March 2018 and June 2020 at a single institution. A total of 77 patients (NETOIMS, 36; intravenous patient-controlled analgesia, 41) were included. NETOIMS was conducted on the retracted intercostal muscle immediately following the main procedure, just before skin closure. Postoperative pain (numeric rating scale) and oral opioid morphine milligram equivalent were assessed daily until postoperative day 5.

RESULTS

The NETOIMS group had a significantly lower numeric rating scale score on postoperative day (POD) 0 (P < .01), POD2 (P < .001), POD4 (P < .001), and POD5 (P = .01). The predicted time to complete pain resolution was 6.15 days in the NETOIMS group and 20.7 days in the intravenous patient-controlled analgesia group. The oral opioid morphine milligram equivalent was significantly lower in the NETOIMS group on POD0 (P < .001) and POD1 (P < .001).

CONCLUSIONS

NETOIMS appears to be an effective modality in alleviating postoperative pain after thoracoscopic surgery, thereby reducing the reliance on opioid use.

Combined T2 Mapping and Diffusion Tensor Imaging: A Sensitive Tool to Assess Myofascial Trigger Points in a Rat Model

Background

Myofascial trigger points (MTrPs) are defined as very small and hypersensitive points in skeletal muscle that are palpable, and produce localized pain on compression. The aim of this study was to explore the feasibility of combining T2 mapping with diffusion tensor imaging (DTI) for assessing MTrPs in a rat model and to investigate properties of the pathophysiological mechanisms.

Methods

Twenty-four Sprague-Dawley rats (model group, n = 14; control group, n = 10) underwent a magnetic resonance imaging (MRI) examination on a 3 T-MRI-scanner with a protocol consisting of T2 mapping and DTI. The MTrPs were established by blunt strike in combination with eccentric exercise. Enzyme-linked immunosorbent assays (ELISAs) were used to detect the levels of interleukin-1ß (IL-1ß) and interleukin-2 (IL-2) and their results were correlated with T2 values. Parameters from MRI including T2 values, fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) were compared between the two groups. Histological analysis was applied to provide an additional supply for MRI findings.

Results

The MTrPs of rats displayed significantly increased T2 values and FA (= 0.000) compared with normal controls, whereas MD and RD values were significantly lower (P= 0.031, = 0.000, respectively). There was no statistically significant difference in AD between the two groups (P= 0.400). These differences were accompanied by elevated levels of IL-1ß and interleukin-2 IL-2 in the MTrP group compared with controls. T2 values were positively correlated with elevated IL-1ß levels (r = 0.543, P < 0.05) but were not correlated with IL-2 levels (P > 0.05).

Conclusion

Combining T2 and DTI sequences creates a sensitive tool to assess MTrPs in a rat model. These data clarify a hypothesis that a trigger point is a chronic and mild muscle injury with inflammation.