Publications by authors named "Hye Rim Suh"

12 Publications

  • Page 1 of 1

Development of a novel model of intervertebral disc degeneration by the intradiscal application of monosodium iodoacetate (MIA) in rat.

Spine J 2021 Jun 9. Epub 2021 Jun 9.

Department of Physiology, Korea University, Seoul, Republic of Korea. Electronic address:

Background Context: Low back pain is one of the most common musculoskeletal disorders. Although, the pathology of intervertebral disc (IVD) degeneration has been modeled using various biological methods, these models are inadequate for simulating similar pathologic states in humans.

Purpose: This study investigated whether monosodium iodoacetate (MIA) injection into the IVD of rats could generate a reliable model of IVD degeneration.

Study Design/settings: In vivo animal study.

Methods: MIA was injected into two-disc spaces (L4-5 and L5-6) of Sprague-Dawley rats. Their behaviors were examined by measuring weight load shifts from hind to forefoot, rearing, and von Frey tests. We examined the inhibition of pain behavior through intraperitoneal morphine injection and measured cyclooxygenase-2 (COX-2) and transcription factor nuclear factor-kappa B (NF-κB) levels in the IVD and dorsal root ganglion (DRG) by Western blot. Bone alterations were assessed by microfocus computed tomography (micro-CT), and IVD and/or cartilage changes were evaluated by hematoxylin and eosin and safranin-O staining and inducible nitric oxide synthase (iNOS) immunohistochemistry. The other authors declare no conflicts of interest. This project funded by the Memorial Fund and the National Research Foundation of Korea (NRF).

Results: We observed increased weight load shifts to the forefoot and decreased rearing. Morphine-injected rats showed reduced pain. NF-κB and COX-2 expression increased in the IVD and left and/or right DRG. Micro-CT analyses suggested progressive bone deformation. Histologic examination showed decreased IVD width and nucleus pulposus area. Cartilaginous changes indicated epiphyseal growth plate loss. Finally, iNOS expression was increased in the subchondral endplate.

Conclusions: These results suggest that low back pain (LBP) models can be developed by MIA injection into the IVDs of rats and that an animal model is useful for exploring degenerative alterations in the affected discs. Therefore, MIA injection may be a useful model for the study of changes in the IVD to elucidate the mechanisms underlying clinical symptoms, such as LBP, in patients with IVD degeneration.

Clinical Significance: This model in which MIA was injected into the disc better represented the human histologic and behavioral characteristics than the existing puncture model.
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http://dx.doi.org/10.1016/j.spinee.2021.06.008DOI Listing
June 2021

Methylene blue induces an analgesic effect by significantly decreasing neural firing rates and improves pain behaviors in rats.

Biochem Biophys Res Commun 2021 Feb 16;541:36-42. Epub 2021 Jan 16.

Department of Physiology, College of Medicine and Neuroscience Research Institute, Korea University, Seoul, South Korea. Electronic address:

Methylene blue (MB) is a blue cationic thiazine dye and currently used in different medical settings. Notably, there have been several attempts to introduce MB for attenuating pain in the last decade. Some clinical studies reported remarkable results, which, however, have been much debated. In addition, accumulating evidence have revealed that MB diminishes voltage-gated sodium channel currents. Accordingly, in the present study, we conducted in vivo experiments, including in vivo single nerve recording and behavioral test, to investigate whether MB dampens neural firing rates and ultimately contributes to pain relief. As a result, neural firing rates significantly decreased and finally converged to zero after MB administration. This event lasted longer than that of lidocaine and was dose-dependently modulated. Furthermore, there was a marked improvement in pain behaviors. The withdrawal threshold and latency of hind paws significantly rose post-MB administration. Therefore, these results demonstrate that MB lessens pain by significantly weakening neural excitability, which implies a strong possibility that this dye may be developed as a pain-relieving medication in the future. This is the first in vivo study to elucidate the effect of MB on nerves and pain relief.
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http://dx.doi.org/10.1016/j.bbrc.2021.01.008DOI Listing
February 2021

Pain-Relieving Effect of 4.4 MHz of Pulsed Radiofrequency on Acute Knee Arthritis in Rats.

Pain Med 2020 08;21(8):1572-1580

Department of Physiology, Korea University College of Medicine, Seoul, Korea.

Objective: Drug injections and surgery are popular treatments for knee joint osteoarthritis. However, these treatments are invasive, and new noninvasive treatments with similar or better efficacy are needed. Here, we evaluated the application of 4.4 MHz of pulsed radiofrequency (PRF) as a new treatment.

Methods: Acute arthritis was induced by injection of carrageenan into the intra-articular space of the knee in male rats. At 4.5 hours after arthritis induction, PRF with the treatment protocol of three seconds on and off was applied to the affected knee joint for 20 minutes. The changes in pain behavior were evaluated by comparing the peak weight load values of both hind paws at pretreatment and four, six, seven, eight, and 24 hours after treatment. And we also used Western blotting and immunohistochemistry to measure the inflammatory changes in the synovial membrane of the inflamed knee.

Results: We found that the 20-minute application of PRF with the treatment protocol significantly recovered the weight load reduction at six-, seven-, and eight-hour time points after carrageenan injection. COX-2 and IL-1β levels were significantly reduced in the inflamed rats after PRF application at six and eight hours post-carrageenan injection. Immunohistochemistry showed that PRF significantly reduced inflammatory cell infiltration at six hours post-carrageenan injection.

Conclusions: . Our results indicate that noninvasive PRF application inhibited pain-related behavior and decreased inflammatory cytokine expression in the inflamed knee joints of rats. Accordingly, PRF application can serve as a potential therapeutic treatment to relieve pain associated with peripheral joint/tissue damage or inflammation.
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http://dx.doi.org/10.1093/pm/pnz264DOI Listing
August 2020

Activation of peripheral group III metabotropic glutamate receptors inhibits pain transmission by decreasing neuronal excitability in the CFA-inflamed knee joint.

Neurosci Lett 2019 02 22;694:111-115. Epub 2018 Nov 22.

Department of Physiology, College of Medicine and Neuroscience Research Institute, Korea University, Seoul, South Korea. Electronic address:

Peripheral group III metabotropic glutamate receptors (mGluRs) function to modulate pain signaling in inflammatory states. Here, we established in vivo experimental settings, including dynamic weight bearing test and in vivo single nerve recording, to elucidate how the group III mGluRs contribute to inhibiting pain transmission at the peripheral sensory nerve terminal in inflammatory states (1 and 3 days) elicited by Complete Freund's Adjuvant (CFA). As a result, CFA-induced nociceptive behaviors were significantly alleviated after administration of 100 and 200 μM L-AP4 (l-2-amino-4-phosphonobutylate; group III mGluR agonist). In addition, neuronal discharges evoked by 6- and 26-g von Frey filaments at the nerve significantly decreased after administration of 200 μM L-AP4. However, this event was not observed in non-inflammatory state. These results suggest that the group III mGluRs negatively regulate nociceptive behavior and pain transmission by lessening neuronal firing rates at the peripheral nerve in inflammation.
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http://dx.doi.org/10.1016/j.neulet.2018.11.033DOI Listing
February 2019

Apoptotic changes in a full-lengthened immobilization model of rat soleus muscle.

Muscle Nerve 2019 02 18;59(2):263-269. Epub 2018 Dec 18.

Department of Physiology, College of Medicine and Neuroscience Research Institute, Korea University, Seoul, 136-705, South Korea.

Introduction: Lengthened immobilization may prevent muscle shortening, and help maintain normal muscle length. However, its apoptotic effects remain unclear. We evaluated the effects of long-term immobilization on apoptotic proteins.

Methods: Rat soleus muscles were immobilized by casting in a neutral (NEUT) or lengthened (LENG) position for 21 days. We evaluated dynamic weight load and muscle atrophy following the 21-day period using hematoxylin and eosin staining. We measured Bax (pro-apoptotic Bcl-2 family member), MyoD (myogenic differentiation factor D), MYH (myosin heavy chain), and cleaved poly(ADP-ribose)polymerase levels and examined apoptotic nucleus expression.

Results: Decreased dynamic weight load and muscle atrophy changes were observed in LENG. Both NEUT and LENG showed significantly reduced levels of MYH. LENG showed a significant increase in Bax and MyoD expression as well as in the number of apoptotic nuclei.

Conclusions: Long-term lengthened immobilization may increase apoptotic changes and decrease muscle formation proteins in muscle. Muscle Nerve 59:263-269, 2019.
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http://dx.doi.org/10.1002/mus.26359DOI Listing
February 2019

Effects of chin tuck exercise using neckline slimmer device on suprahyoid and sternocleidomastoid muscle activation in healthy adults.

J Phys Ther Sci 2018 Mar 2;30(3):454-456. Epub 2018 Mar 2.

Department of Physical Therapy, Gachon University: 191 Hambangmoe-ro, Yeonsu-gu, Incheon 21936, Republic of Korea.

[Purpose] This study investigated the effect of chin tuck exercise (CTE) using a neckline slimmer device on suprahyoid (SH) and sternocleidomastoid (SCM) muscle activation in healthy adults. [Subjects and Methods] We measured activation of the SH and SCM muscles using surface electromyography in 20 healthy adults during head lift exercise (HLE) and CTE using a neckline slimmer device. The order of exercises was randomized and the mean and peak values of each muscle's activation were assessed. [Results] During the CTE using a neckline slimmer device, SH activation was significantly greater and SCM activation was significantly lower than during the HLE. [Conclusion] This study suggest that chin-tuck exercise using a neckline slimmer device may be more helpful than HLE for swallowing training.
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http://dx.doi.org/10.1589/jpts.30.454DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5857457PMC
March 2018

The ratio of medial and lateral hamstring muscle thickness does not correlate with the lateral tibial rotation angle in the standing position in healthy young adults.

J Phys Ther Sci 2017 Apr 20;29(4):618-621. Epub 2017 Apr 20.

Department of Physical Therapy, Division of Health Science, Baekseok University, Republic of Korea.

[Purpose] To investigate the relationship between the lateral tibial rotation angle during knee joint flexion and the medial and lateral hamstring muscle thickness ratio during knee joint extension while resting, doing nothing, in upright standing position. The lateral tibial torsion is an important factor of orthopedic knee joint diseases as well as other weight bearing joint diseases such as osteoarthritis, meniscus syndrome, anterior cruciate ligament rupture, etc. [Subjects and Methods] Thirty healthy young adults participated in this study. The thickness of the medial and lateral hamstrings was measured using ultrasonographic imaging technique during knee extension in a resting position. The angle of tibial rotation was measured with 2D motion analysis during knee flexion in a half kneeling position. Pearson's correlation coefficient was used to test the relationship. [Results] There is no significant relationship between the angle of lateral tibial rotation and the ratio of hamstring muscle thickness. [Conclusion] These results demonstrate that lateral tibial rotation is not affected by hamstrings during rest in a standing position.
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http://dx.doi.org/10.1589/jpts.29.618DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5430259PMC
April 2017

The contribution of activated peripheral kappa opioid receptors (kORs) in the inflamed knee joint to anti-nociception.

Brain Res 2016 10 1;1648(Pt A):11-18. Epub 2016 Jul 1.

Department of Physiology, College of Medicine and Neuroscience Research Institute, Korea University, Seoul 136-701, South Korea. Electronic address:

The systemic administration of opioids can be used for their strong analgesic effect. However, extensive activation of opioid receptors (ORs) beyond the targeted tissue can cause dysphoria, pruritus, and constipation. Therefore, selective activation of peripheral ORs present in the afferent fibers of the targeted tissue can be considered a superior strategy in opioid analgesia to avoid potential adverse effects. The purpose of this study was to clarify the role of peripheral kappa opioid receptors (kORs) in arthritic pain for the possible use of peripheral ORs as a target in anti-nociceptive therapy. We administered U50488 or nor-BNI/DIPPA, a selective agonist or antagonist of kOR, respectively into arthritic rat knee joints induced using 1% carrageenan. After the injection of U50488 or U50488 with nor-BNI or DIPPA into the inflamed knee joint, we evaluated nociceptive behavior as indicated by reduced weight-bearing on the ipsilateral limbs of the rat and recorded the activity of mechanosensitive afferents (MSA). In the inflamed knee joint, the intra-articular application of 1μM, 10nM, or 0.1nM U50488 resulted in a significant reduction in nociceptive behavior. In addition, 1μM and 10nM U50488 decreased MSA activity. However, in a non-inflamed knee joint, 1μM U50488 had no effect on MSA activity. Additionally, intra-articular pretreatment with 20μM nor-BNI or 10μM DIPPA significantly blocked the inhibitory effects of 1μM U50488 on nociceptive behavior and MSA activity in the inflamed knee joint. These results implicate that peripheral kORs can contribute to anti-nociceptive processing in an inflamed knee joint.
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http://dx.doi.org/10.1016/j.brainres.2016.06.048DOI Listing
October 2016

The Effects of High-Frequency Transcutaneous Electrical Nerve Stimulation for Dental Professionals with Work-Related Musculoskeletal Disorders: A Single-Blind Randomized Placebo-Controlled Trial.

Evid Based Complement Alternat Med 2015 17;2015:327486. Epub 2015 Nov 17.

Department of Dental Hygiene, Gachon University College of Health Science, Incheon 21936, Republic of Korea.

Work-related musculoskeletal symptom disorders (WMSDs) have a significant issue for dental professionals. This study investigated the effects of high-frequency transcutaneous electrical nerve stimulation (TENS) on work-related pain, fatigue, and the active range of motion in dental professionals. Among recruited 47 dental professionals with WMSDs, 24 subjects received high-frequency TENS (the TENS group), while 23 subjects received placebo stimulation (the placebo group). TENS was applied to the muscle trigger points of the levator scapulae and upper trapezius, while placebo-TENS was administered without electrical stimulation during 60 min. Pain and fatigue at rest and during movement were assessed using the visual analog scale (VAS), pain pressure threshold (PPT), and active range of motion (AROM) of horizontal head rotation at six time points: prelabor, postlabor, post-TENS, and at 1 h, 3 h, and 1 day after TENS application. Both groups showed significantly increased pain and fatigue and decreased PPT and AROM after completing a work task. The TENS group showed significantly greater improvements in VAS score, fatigue, PPT, and AROM at post-TENS and at 1 h and 3 h after application (all P < 0.05) as compared to the placebo group. A single session high-frequency TENS may immediately reduce symptoms related to WMSDs in dental professionals.
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http://dx.doi.org/10.1155/2015/327486DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4664811PMC
December 2015

The effects of Chamaecyparis obtusa essential oil on pain-related behavior and expression of pro-inflammatory cytokines in carrageenan-induced arthritis in rats.

Biosci Biotechnol Biochem 2016 19;80(1):203-9. Epub 2015 Aug 19.

a Department of Physiology , College of Medicine and Neuroscience Research Institute, Korea University , Seoul , South Korea.

Chamaecyparis obtusa essential oil (COE) has been widely used to treat allergic diseases and was suggested to exert anti-inflammatory, antioxidant, and antimicrobial effects. This study evaluated the effects of COE on pain-related behavior and pro-inflammatory cytokines in rats with carrageenan (CGN)-induced arthritis. Reduced dynamic weight load on inflamed joint in voluntarily walking rats was used as the behavior test for arthritic pain; 10% COE-treated group was significantly attenuated pain (6-8 h post-CGN injection) compared to VEH (mineral oil)-treated group. In addition, the protein levels of interleukin (IL)-1β, tumor necrosis factor-α, IL-6 (6-8 h), and cyclooxygenase (COX)-2 (8 h) within the synovial membrane, as well as IL-1β, COX-2 (6-8 h), and IL-6 (5-7 h) within the meniscus, of 10% COE-treated group were significantly reduced. The current results implicate that COE has anti-inflammatory and anti-nociceptive effects on arthritis in rats.
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http://dx.doi.org/10.1080/09168451.2015.1075864DOI Listing
September 2016

A single trial of transcutaneous electrical nerve stimulation reduces chronic neuropathic pain following median nerve injury in rats.

Tohoku J Exp Med 2014 03;232(3):207-14

Department of Physical Therapy, Gachon University College of Health Science.

Neuropathic pain is a devastating chronic condition and is often induced in the upper limb following nerve injury or damage. Various drugs or surgical methods have been used to manage neuropathic pain; however, these are frequently accompanied by undesirable side effects. Transcutaneous electrical nerve stimulation (TENS) is a safe and non-invasive intervention that has been used to alleviate different types of pain in the clinic, but it is unclear whether TENS can improve chronic neuropathic pain in the upper limb. Thus, the aim of this study was to investigate the effects of a single trial of TENS on chronic neuropathic pain following median nerve injury. Male rats weighing 200-250 g received median nerve-ligation of the right forearm, while the control group received only skin-incision without nerve-ligation. Neuropathic pain-behaviors, including mechanical, cold, and thermal allodynia, were measured for 4 weeks. After the development of chronic neuropathic pain, TENS (100 Hz, 200 µs, sub-motor threshold) or placebo-TENS (sham stimulation) was applied for 20 min to the ipsilateral or contralateral side. Neuropathic pain behavior was assessed before and after intervention. Median nerve-ligation significantly induced and maintained neuropathic pain in the ipsilateral side. TENS application to the ipsilateral side effectively attenuated the three forms of chronic neuropathic pain in the ipsilateral side compared to sham-treated rats (peripheral and central effects), while TENS application to contralateral side only reduced mechanical allodynia in the ipsilateral side (central effect). Our findings demonstrate that TENS can alleviate chronic neuropathic pain following median nerve injury.
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http://dx.doi.org/10.1620/tjem.232.207DOI Listing
March 2014

Immediate therapeutic effect of interferential current therapy on spasticity, balance, and gait function in chronic stroke patients: a randomized control trial.

Clin Rehabil 2014 Sep 7;28(9):885-91. Epub 2014 Mar 7.

Department of Physical Therapy, College of Health Science, Gachon University, Incheon, South Korea

Objective: To determine whether a single trial of interferential current therapy (ICT) can immediately alleviate spasticity and improve balance and gait performance in patients with chronic stroke.

Design: Randomized, placebo-controlled clinical trial.

Setting: Inpatient rehabilitation in a local center.

Subjects: A total of 42 adult patients with chronic stroke with plantar flexor spasticity of the lower limb.

Intervention: The ICT group received a single 60-minute ICT stimulation of the gastrocnemius in conjunction with air-pump massage. In the placebo-ICT group, electrodes were placed and air-pump massage performed without electrical stimulation.

Main Measures: After a single ICT application, spasticity was measured immediately using the Modified Ashworth Scale (MAS), and balance and functional gait performance were assessed using the following clinical tools: Functional Reach Test (FRT), Berg Balance Scale (BBS), Timed Up and Go Test (TUG), and 10-m Walk Test (10MWT).

Results: Gastrocnemius spasticity significantly decreased in the ICT group than in the placebo-ICT group (MAS: ICT vs placebo-ICT: 1.55±0.76 vs 0.40±0.50). The ICT group showed significantly greater improvement in balance and gait abilities than the placebo-ICT group (FRT: 2.62±1.21 vs 0.61±1.34, BBS: 1.75±1.52 vs 0.40±0.88, TUG: 6.07±6.11 vs 1.68±2.39, 10MWT: 7.02±7.02 vs 1.96±3.13). Spasticity correlated significantly with balance and gait abilities (P < 0.05).

Conclusion: A single trial of ICT is a useful intervention for immediately improving spasticity, balance, and gait abilities in chronic stroke patients, but not for long-term effects. Further study on the effects of repeated ICT is needed.
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http://dx.doi.org/10.1177/0269215514523798DOI Listing
September 2014
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