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-ß1)-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-ß1)-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-ß1 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-ß1 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-ß1 were positive. Conclusion: Fibrotic conditions may be involved in the formation of MTrPs. Ultrasound point shear wave elastography and assessment of TGF-ß1 and p-Smad2/3 expression can reflect the degree of MTrPs fibrosis to some extent. Further exploration of the important role of TGF-ß1 and Smad2/3 in the pathogenesis of MTrPs will be of great significance for clinical treatment.

Sonographic Assessment of Oropharynx Movement During Deep Breathing.

To investigate the feasibility of ultrasonography in detecting the oropharynx movement during deep breathing and to quantitatively analyze oropharynx airway lumen changes during deep breathing. The motions of oropharynx were monitored, and sonographic measurements of airway lumen were obtained during deep breathing in 448 healthy volunteers. Adequate visualization of oropharynx movement was obtained on all healthy volunteers. The anterior-posterior (AP) diameters and AP/transverse (T) diameter ratios were greater at the end of deep inspiration than that at the end of deep expiration for each sex (p < 0.01). The anterior-posterior dimensional changes were greater than lateral airway dimensional changes each sex (p < 0.05). Ultrasonography could provide realistic impression of the process on the oropharynx movement during deep breathing and perform the quantitative analysis of the oropharynx airway lumen changes during deep breathing. The results were encouraging and supported the utility of ultrasonography in future studies.