• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.528-532
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• 2019

본 연구는 뉴런 세포와 슈반 세포의 공동 배양에 의한 수초화 발생 과정과 herpes simplex virus-1 감염에 의한 탈수초화 발생과정을 전자 현미경과 분자생물학적 분석에 의하여 확인하고자 하였다. 쥐의 배아로부터 후근신경절(dorsal root ganglion, DRG)을 분리하여 슈반(Schwann) 세포와 뉴런 세포(neuronal cell)를 in vitro에서 각각 배양하였다. 유사 분열 억제인자로 처리한 뉴런세포와 정제된 슈반 세포를 함께 공동 배양을 하여 수초화를 발생시켰다. 이렇게 수초화된 공동 배양 세포에 herpes simplex virus-1를 감염시켜 탈수초화를 진행시켰다. 수초 형성의 존재를 의미하는 myelin protein zero(MPZ) 항체를 사용하고 전자 현미경을 이용하여 수초 발생 및 탈수초화 과정을 관찰하였다. 이 연구는 과학 기술부, ICT 및 미래 계획 (NRF-2016R1A2B4016552 및 2017R1A2B3005753)이 자금을 지원하는 국립 연구 재단 (NRF)을 통한 기초 연구 프로그램의 지원을 받았다.

• The Korean Journal of Pain
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• 제35권1호
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• pp.114-123
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• 2022

Background: Different views have been proposed on the radiofrequency treatment modes and parameters of radiofrequency thermocoagulation of the spinal dorsal root ganglion for the treatment of postherpetic neuralgia (PHN). It is urgent to identify a more effective therapy for patients with PHN. Methods: Patients who underwent radiofrequency thermocoagulation therapy for PHN were retrospectively reviewed and were divided into a radiofrequency thermocoagulation (CRF) and double neddles radiofrequency thermocoagulation (DCRF). The pain scores (numerical rating scale, NRS) were evaluated at the following time points: before the operation, 1 day, 3 months, 6 months, 1 year, and 2 years after operation. The incidence of complications and the degree of pain relief were evaluated. The in vitro ovalbumin experiment was used to indicate the effects of radiofrequency thermocoagulation. Results: Compared with the preoperative NRS scores, the postoperative NRS scores decreased significantly; the NRS scores of the DCRF group was lower than that of the CRF group at all time points from 6 months to 2 years following the operation. The total effective rate of the DCRF group was significantly higher than that of the CRF group at 2 years following the operation. The incidence of numbness in the DCRF group was higher than that noted in the CRF group. The ovalbumin experiments in vitro indicated that the effects of radiofrequency thermocoagulation were optimal when the distance between the two needles was 5 mm. Conclusions: DCRF with a 5 mm spacing exhibits a longer duration and higher effective rate in the treatment of PHN and is worth promoting.

• Archives of Pharmacal Research
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• 제27권11호
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• pp.1154-1160
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• 2004

We investigated the neurotoxic effects of capsaicin (CAP) on pain sensitivity and on the expression of capsaicin receptor, the vanilloid receptor (VR1), in rats. High-dose application of CAP has been known to degenerate a large fraction of the sensory neurons. Although the neurotoxic effects of CAP are well documented, the effects of CAP on the vanilloid receptor (VR1) are not yet known. In this paper, we investigated the effects of high-dose application of CAP on the expression of VR1 in rats. Thermal and mechanical pain sensitivity was reduced when neonatal rats were treated with a high dose of CAP. This reduction of pain sensitivity was significantly decreased after initiating carrageenan-induced inflammation. The expression of VR1 in dorsal root ganglia (DRG) isolated from the CAP-treated rats was reduced compared to that from the vehicle-treated rats. Therefore, we can conclude that the neurotoxic effect of CAP is related to the decrease of VR1 expression.

• Animal cells and systems
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• 제15권3호
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• pp.181-187
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• 2011

Transient receptor potential vanilloid type 1 (TRPV1) receptor plays an important role as a molecular detector of noxious signals in primary sensory neurons. Activity of TRPV1 can be modulated by the change in the environment such as redox state and extracellular cations. In the present study, we investigated the effect of the mercury chloride ($HgCl_2$) on the activity of TRPV1 in rat dorsal root ganglia (DRG) neurons using whole-cell patch clamp technique. Extracellular $HgCl_2$ reversibly reduced the magnitudes of capsaicin-activated currents ($I_{cap}$) in DRG neurons in a dose-dependent manner. The blocking effect of $HgCl_2$ was prevented by pretreatment with the reducing agent dithiothreitol (DTT). Inhibition of $I_{cap}$ by $HgCl_2$ was abolished by point mutation of individual cysteine residues located on the extracellular surface of TRPV1. These results suggest that three extracellular cysteines of TRPV1, Cys616, Cys634 and Cys621, are responsible for the oxidative modulation of $I_{cap}$ by $HgCl_2$.

• The Korean Journal of Pain
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• 제20권2호
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• pp.203-207
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• 2007

Inguinal hernia repair can result in paresthesia and/or pain in the inguinal region. Pharmacological and surgical management often yield inconsistent results associated with considerable risks and side effects. Radiofrequency thermocoagulation (RF) is a neuro-destructive treatment for severe pain, but associated with hypoesthesia, neuritis-like reactions, and occasional neuroma formation. Pulsed radiofrequency (PRF), unlike RF, delivers high intensity currents in pulses, is non-neurodestructive, and therefore less painful, without the potential complications. Here we report on PRF in chronic postoperative inguinal pain. A 23-year-old male who received right inguinal hernia repair and complained of right sided groin pain for approximately 10 years underwent PRF at the L1 and L2 dorsal root ganglia (DRG). He then reported a decrease in pain from 80-90/100 mm to 15-30/100 mm on a visual analogue scale (VAS), which lasted for twelve months.

• The Korean Journal of Pain
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• 제25권3호
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• pp.191-194
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• 2012

Tarlov or perineural cysts are nerve root cysts found most commonly at the sacral spine level arising between covering layers of the perineurium and the endoneurium near the dorsal root ganglion and are usually asymptomatic. Symptomatic sacral perineural cysts are uncommon but sometimes require surgical treatment. A 69-year-old male presented with pain in the buttock. He was diagnosed as having a sacral cyst with magnetic resonance imaging. For the nonoperative diagnosis and treatment, caudal peridurography and block were performed. After the treatment, the patient's symptom was relieved. We suggest a caudal peridural block is effective in relieving pain from a sacral cyst.

• International Journal of Oral Biology
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• 제38권1호
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• pp.13-19
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• 2013

Various voltage-gated $K^+$ currents were recently described in dorsal root ganglion (DRG) neurons. However, the characterization and diversity of voltage-gated $K^+$ currents have not been well studied in trigeminal root ganglion (TRG) neurons, which are similar to the DRG neurons in terms of physiological roles and anatomy. This study was aimed to investigate the characteristics and diversity of voltage-gated $K^+$ currents in acutely isolated TRG neurons of rat using whole cell patch clamp techniques. The first type (type I) had a rapid, transient outward current ($I_A$) with the largest current size having a slow inactivation rate and a sustained delayed rectifier outward current ($I_K$) that was small in size having a fast inactivation rate. The $I_A$ currents of this type were mostly blocked by TEA and 4-AP, K channel blockers whereas the $I_K$ current was inhibited by TEA but not by 4-AP. The second type had a large $I_A$ current with a slow inactivation rate and a medium size-sustained delayed $I_K$ current with a slow inactivation rate. In this second type (type II), the sensitivities of the $I_A$ or $I_K$ current by TEA and 4-AP were similar to those of the type I. The third type (type III) had a medium sized $I_A$ current with a fast inactivation rate and a large sustained $I_K$ current with the slow inactivation rate. In type III current, TEA decreased both $I_A$ and $I_K$ but 4-AP only blocked $I_A$ current. The fourth type (type IV) had a smallest $I_A$ with a fast inactivation rate and a large $I_K$ current with a slow inactivation rate. TEA or 4-AP similarly decreased the $I_A$ but the $I_K$ was only blocked by 4-AP. These findings suggest that at least four different voltage-gated $K^+$ currents in biophysical and pharmacological properties exist in the TRG neurons of rats.

• The Journal of Korean Physical Therapy
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• 제21권3호
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• pp.95-102
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• 2009

Purpose: This study evaluates MCP-1 expression in the dorsal horn of a rat model of lumbar disc herniation by an autograft of the nucleus pulposus to the spinal nerve. Methods: After a coccygeal nucleus pulposus graft to the left $5^{th}$ lumbar spinal nerve, proximal to dorsal root ganglion, mechanical allodynia and thermal hyperalgesia were assessed 1 day before surgery, and 1, 10, 20, 30 days after surgery. The mRNA of MCP-1 in the dorsal horn was assessed by real time PCR to compare the temporal pattern of neuropathic pain of the lumbar disc herniation model. Results: In the ipsilateral side of the lumbar disc herniation models, mechanical allodynia and thermal hyperalgesia reached a maximum at 10 days after surgery with significant difference from the control group. Pain was also provoked in the contralateral side of the lumbar disc herniation models with less intensity than the ipsilateral side. The level of MCP-1 mRNA expression in the dorsal horn reached a peak at 20 days after surgery. Conclusion: Mechanical allodynia and thermal hyperalgesia was induced by nucleus pulposus in a rat lumbar disc herniation model, similar to a previously reported peripheral nerve injury model. The level of MCP-1 expression was higher in the dorsal horn of the ipsilateral and contralateral sides. These results suggest that MCP-1 might play a role in the maintenance of neuropathic pain.

• The Korean Journal of Physiology and Pharmacology
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• 제14권1호
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• pp.45-49
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• 2010

R-type $Ca_v2.3$ high voltage-activated $Ca^{2+}$ channels in peripheral sensory neurons contribute to pain transmission. Recently we have demonstrated that, among the six $Ca_v2.3$ isoforms ($Ca_v2.3a{\sim}Ca_v2.3e$), the $Ca_v2.3e$ isoform is primarily expressed in trigeminal ganglion (TG) nociceptive neurons. In the present study, we further investigated expression patterns of $Ca_v2.3$ isoforms in the dorsal root ganglion (DRG) neurons. As in TG neurons, whole tissue RT-PCR analyses revealed the presence of two isoforms, $Ca_v2.3a$ and $Ca_v2.3e$, in DRG neurons. Single-cell RT-PCR detected the expression of $Ca_v2.3e$ mRNA in 20% (n=14/70) of DRG neurons, relative to $Ca_v2.3a$ expression in 2.8% (n=2/70) of DRG neurons. $Ca_v2.3e$ mRNA was mainly detected in small-sized neurons (n=12/14), but in only a few medium-sized neurons (n=2/14) and not in large-sized neurons, indicating the prominence of $Ca_v2.3e$ in nociceptive DRG neurons. Moreover, $Ca_v2.3e$ was preferentially expressed in tyrosine-kinase A (trkA)-positive, isolectin B4 (IB4)-negative and transient receptor potential vanilloid 1 (TRPV1)-positive neurons. These results suggest that $Ca_v2.3e$ may be the main R-type $Ca^{2+}$ channel isoform in nociceptive DRG neurons and thereby a potential target for pain treatment, not only in the trigeminal system but also in the spinal system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권2호
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• pp.100-107
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• 2004

Schwann cell, one of important components of peripheral nervous system, interact with neurons to mutually support the growth and replication of embryonal nerves and to maintain the different functions of adult nerves. The Ara-C, known as an antimitotic agent, have been used to have high effectiveness in eliminating fibroblasts during Schwann cell culture period. This enrichment effect is also known to be cummulative with each successive pulse of Ara-C applied and is due to a progressive loss of fibroblasts. But the cytotoxicity by Ara-C is also cummulative and noticeable over the period. To determine the most effective application time and interval of Ara-C in the Schwann cell culture, we observed the Schwann cell purity and density with the Ara-C treatment in plain and three-dimensional culture from dorsal root ganglion of new born rat. By culturing dispersed dorsal root ganglia, we can repeatedly generate homogenous Schwann cells, and cellular morphology and cell count with mean percentages were evaluated in the plain culture dishes and in the immunostainings of S-100 and GFAP in the three-dimensional culture. The Ara-C treated cultures showed a higher Schwann cell percentage ($31.0%{\pm}8.09%$ in P4 group to $65.5%{\pm}24.08%$ in P2 group), compared with that obtained in the abscence of Ara-C ($17.6%{\pm}6.03%$) in the plain culture after 2 weeks. And in the three-dimensional culture, S-100 positive cells increased to $56.22%{\pm}0.67%$ and GFAP positive cells to $66.46%{\pm}1.83%$ in G2 group (p<0.05), higher yield than other groups with Ara-C application. Therefore, we concluded that the Ara-C treatment is effective for the proliferation of Schwann cells contrast to the fibroblasts in vitro culture, and the first application after 24 hours from cell harvesting and subsequent 2 pulse treatment (P2 group in plain culture and G2 group in three-dimensional culture) was more effective than other application protocols.