J Dent Hyg Sci Vol. 15, No. 6, 2015, pp.800-806 http://dx.doi.org/10.17135/jdhs.2015.15.6.800 RESEARCH ARTICLE 흰쥐의측두하악관절통증모델에서 Triptolide 와 N-nitro-L-arginine Methyl Ester 의통증조절효과 김윤경ㆍ이민경 동의대학교일반대학원보건의과학과 Analgesic Effects of Triptolide and N-nitro-L-arginine Methyl Ester in Rat s Temporomandibular Joint Pain Model Yun-Kyung Kim and Min-Kyung Lee Department of Biomedical Health Science, Dong-Eui University, Busan 47340, Korea The aim of this study was to investigate whether intracisternal administrations of triptolide and N-nitro-L-arginine Methyl Ester (L-NAME) are involved in the regulation of temporomandibular joint (TMJ) pain. The TMJ pain was induced by the injection of 5% formalin (30 l) into TMJ capsule of rats. The pain behavioral responses was recorded the number of grooming or scratching on the left TMJ area for 9 successive 5 minutes intervals. Triptolide and L-NAME were administrated intracisternally 10 minutes before formalin injection. The intra-articular injection of formalin produced a biphasic pattern of pain response (first phase: 0 10 minutes and second phase: 11 45 minutes). The intracisternal administration of triptolide (1 g/10 l) and L-NAME (0.1 g/10 l) suppressed the TMJ pain behavior in each experiment. Co-administration of two drugs was shown the enhanced effect than the analgesic effect by single-administration of triptolide (1 g/10 l). The triptolide could be a useful analgesic agent for the treatment of TMJ pain, and it is expected to reduce the substantial amount of it via co-administration of synthetic chemical compound and natural products. Key Words: Analgesic effect, L-NAME, Pain, Temporomandibular joint, Triptolide 서론 측두하악관절 (temporomandibular joint, TMJ) 은측두골과하악골의연결시켜주는관절을지칭하고인체의여타관절과는다른특유의해부학적구조를가지고있으며, 저작근, 인대, 신경, 치아및치주조직등에의해측두하악관절만의고유한입체적운동을하는저작계의고유구성성분이다 1). 측두하악관절내에발생한염증이나탈구등의기능장애로측두하악관절장애 (TMJ disorders) 가유발되면측두하악관절잡음, 개구제한등의증상들이나타나며, 이러한증상들중통증은측두하악관절장애환자가가장흔히호소 하는대표적인증상이다 2,3). 미국의경우, 전국민의 65 85% 가측두하악관절장애의다양한증상을경험하며, 이들중 12% 는지속되는통증이나활동불구로인해고통받는다고보고된바있다 4,5). 이러한측두하악관절장애로인한통증을치료하기위해염증반응의주요매개체를억제하는비스테로이드성약물 (non-steroidal anti-inflammatory drugs) 이주로사용되고있으나이들약물은위장관독성, 특히장기간복용시혈전증등의부작용을일으킬수있어 6) 그사용에주의가요구된다. 이에따라, 최근에는비교적독성이적고건강식품으로서주목받고있는천연물을이용한통증조절효과에대한연구가이어지고있다 7). Received: November 4, 2015, Revised: November 25, 2015, Accepted: November 25, 2015 Correspondence to: Min-Kyung Lee Department of Biomedical Health Science, Dong-Eui University, 176 Eomgwang-ro, Busanjin-gu, Busan 47340, Korea Tel: +82-51-890-4238, Fax: +82-0505-182-6878, E-mail: lmk849@deu.ac.kr ISSN 1598-4478 (Print) / ISSN 2233-7679 (Online) Copyright 2015 by the Korean Society of Dental Hygiene Science This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
김윤경ㆍ이민경 :Triptolide 와 L-NAME 의악관절통증조절효과 Triptolide는중국의전통약초인미역순나무 (Tripterygium wilfordii Hook F.) 에서추출한활성성분의하나로항염증및통증경감등의효과가있다고보고되었다. 이와관련한연구로, 척수신경결찰에의한신경병증성통증모델에서증가된기계적이질통은 triptolide의복강투여 8) 또는척수강내투여 9) 로인해각각완화되었고, 유선암종세포의골수강내주입으로유도된실험동물의골암통증모델에서척수강내투여한 triptolide는뒷발바닥에증가된기계적통각과민반응을완화시켰다 10). 또한실험동물의발바닥에주입한 complete Freund s adjuvant (CFA) 에의해증가된열및기계적통증반응은 triptolide의복강투여로인해완화되었다고보고되며 11) 이러한연구결과들은 triptolide의통증경감효과를뒷받침하고있다. 그러나아직까지 triptolide의통증경감효과를측두하악관절통증모델에서연구한보고는미미한실정이다. 측두하악관절의통증전도과정에는다양한염증성매개인자들이관여하며, 그중 nitric oxide (NO) 의합성효소인 inducible nitric oxide synthase (inos) 는측두하악관절의염증에서증가되어나타난다고보고된다 12). N-nitro-L-arginine Methyl Ester (L-NAME) 는 NO의합성억제제로, L-NAME 의적용은통증발생의억제에효과적인것으로알려져있다 13,14). 실험동물의안면부에주입한 interleukin (IL)-1 로인해유도된기계적이질통은 L-NAME의투여로인해감소되었고 15), 포르말린으로유도한안면부통증모델에서소뇌연수조로의 L-NAME 투여가통증행위반응을감소시켰다는 16) 보고들은 L-NAME의염증성통증조절효과를입증하는연구결과이다. 진통효과를얻기위해약물을단독투여하거나두가지이상의약물을병용하여투여할수있다. 임상에서는약물의병용투여가단독투여시보다약물의흡수촉진및상가적작용으로좋은효과를기대할수있거나부작용의예방및감소가가능하다면, 각각의약물투여용량을감소시킬수있다 17). 이러한원리를적용한최근연구로, 포르말린으로유도된염증성통증모델에서 L-NAME와 morphine의병용투여가약물의상승적상호작용을나타내었다고보고된바있으나 18) 천연물과의상호작용에대한연구는매우부족한실정이다. 따라서이번연구에서는포르말린으로유도한측두하악관절통증모델에서천연물질인 triptolide와 L-NAME를각각소뇌연수조로투여하여통증행위반응에미치는영향을평가하고, 또한두약물의병용투여에의한약물의상호작용을평가하고자하였다. 연구대상및방법 1. 실험동물실험동물은 240 280 g의 Sprague-Dawley계수컷흰쥐를효창사이언스 (Daegu, Korea) 에서공급받아사용하였다. 실험용플라스틱상자에서사료와물을자유로이공급하면서 23 25 o C의온도및 12시간주 / 야순환주기의일정한환경을유지하면서사육하였다. 이연구는의식이있는동물의실험에관한통증연구학회의윤리적규정에따라수행하였으며, 동의대학교동물실험윤리위원회의연구승인 (R2015-001) 을얻은후실시하였다. 2. 약물투여 Triptolide (Sigma, St. Louis, MO, USA) 와 L-NAME (Sigma) 는각각 5% dimethylsulfoxide와 0.9% 생리식염수에희석하여 70 o C에서보관하였다. Vehicle (10 l), triptolide1 (1, 0.1 g/10 l) 및 L-NAME (0.1, 0.01 g/10 l) 는실험직전사용농도로희석하였으며, 포르말린주입 10분전 Hamilton 주사기 (Hamilton Co., Reno, NV, USA) 를사용하여소뇌연수조내로투여하였다. 두약물의병용투여는 1 g/10 l의 triptolide와 0.01 g/10 l의 L-NAME 를혼합하여동일한과정으로진행하였다. 통증행위반응을유발하기위하여 5% 포르말린은생리식염수에희석하여실험동물의안면부에주입하였다. 3. 포르말린으로유도한측두하악관절통증실험동물의스트레스를최소화하기위해실험전실험용플라스틱통에 10분이상적응시킨뒤관절강내포르말린주입을위해흡입마취하였다. 마취된직후관절강내로 30 l 의포르말린을주입하였고, 실험동물은포르말린주입후수초내에의식을회복하는것을관찰하였다. 포르말린주입을위한 cannula는폴리에틸렌튜브한쪽끝에 30 gauge 주사바늘을연결하였고, 반대쪽에는인슐린주사기 (0.25 8 mm) 를연결하여사용하였다. 관골궁의후하방경계면과하악과두의촉지에의해관절강의위치를유추하였고, 해당부위에주사바늘이관절낭을뚫고하악와의닿는부위를관절강내로인지하였다. 이는실험전포르말린과동일한양의 1% Evans blue dye를별도의동물에주입하여악관절강의위치를확인하였다. 포르말린주입후측두하악관절부위를문지르거나긁는행위반응을통증지표로간주하여 5분간격으로 45분간누적하여기록하고, 1차반응 (0 10분, first phase) 과 2차반응 (11 45분, second phase) 으로구분하여평가하였다 19). 801
J Dent Hyg Sci Vol. 15, No. 6, 2015 4. 약물투여를위한중추로의카테터삽입소뇌연수조로약물을투여하기위한카테터삽입수술은선행연구 20) 를따라시행하였다. 실험동물은 zoletil (1 ml/kg) 과 xylazine (0.25 ml/kg) 의병용액을근육주사하여마취하였다. 마취된쥐의뒤통수부위를면도하여 stereotaxic frame (Model 1404; David Kopf Instruments, Tujunga, CA, USA) 에고정시키고정수리점부터뒤통수뼈아래까지피부를절개하였다. 후두근을포함한주변근육을젖혀노출된뇌척수막에 26 gauge의주사바늘로작은구멍을내어뇌척수액의미세유출을확인후폴리에틸렌카테터 (8 cm, PE10; Caly Adams, Parsippany, NJ, USA) 를약 1 2 mm 삽입하였다. 카테터는마루뼈에미리삽입된 mini screw에회전시켜치과용자가중합레진 (Dentsply, York, PA, USA) 으로두개골에고정하였고, 카테터끝은뇌척수액의흐름을방지하기위하여 stainless steel wire (0.32 mm) 로막아두었다. 절개부위는 4-0 나일론봉합사로봉합하였고, gentamycin (0.05 ml/kg) 을근육주사하였다. 술후실험동물은각각플라스틱통에보관하였고, 72시간이상회복후실험에사용되었다. 5. 통계분석반복측정자료는 IBM SPSS Statistics ver. 19.0 (IBM Co., Armonk, NY, USA) 를이용하여 LSD (least significant difference) 사후분석법을적용한일원배치분산분석을하였고, 실험결과는 Sigmaplot 2001 (SPSS Inc, Chicago, IL, USA) 을이용하여그래프로나타내었다. 통계적인비교를위해통계적유의성의표준값은 p<0.05로설 정하였으며, 결과는평균 ± 표준오차 (standard error of mean, SEM) 로표시하였다. 결과 1. Triptolide의측두하악관절통증조절효과실험동물의관절강내에포르말린을주입하여유도된측두하악관절통증모델에서 triptolide의소뇌연수조투여로인한통증조절효과는다음결과와같다. 먼저그래프에나타내지는않았지만, 예비실험에서관절강내포르말린주입군은아무것도처치하지않은군에비해통증행위반응이유의하게증가됨을확인하였다. 1차통증행위반응의결과, 소뇌연수조로 triptolide (0.1, 1 g/10 l) 투여후포르말린을주입한군은각농도에따라통증행위반응수치가 29.50± 9.78회, 22.50±19.15회로나타났으며, 25.83±5.44회로나타난포르말린주입군과비교시유의한차이를나타내지않았다. 하지만 2차통증행위반응의결과, 포르말린주입군 (308±33.04회) 과비교하여 triptolide 주입군에서농도에따라 217.00±30.95, 163.33±29.11로통증행위반응이유의하게감소됨을확인하였다. 반면에 vehicle 주입군의 1, 2차통증행위반응을관찰한결과, 각각 45.83± 22.72회, 65.67±32.02로통증조절에영향을미치지않는다는것을확인하였다 (Fig. 1). 통증행위반응의변화를시간의경과에따라보면, 소뇌연수조로 triptolide (1 g/10 l) 투여후포르말린을주입한실험군의통증행위반응은포르말린주입군과비교시주입 20분후에가장유의하게감소되었음을확인하였다 (Fig. 2). Fig. 1. Effects of triptolide on temporomandibular joint (TMJ) nociceptive behavior. The nociceptive responses were reduced in 2nd phase (11 45 min), following intracisternal administration of triptolide 10 min before formalin injection into TMJ capsule (n=6). *p<0.05, formalin (F) vs. triptolide 1 g+f. Fig. 2. Changes in nociceptive responses following intracisternal administration of triptolide. The administration of triptolide into temporomandibular joint (TMJ) capsule reduced the nociceptive responses 20 min after induction of TMJ pain. *p<0.05, formalin (F) vs. triptolide 1 g+f. 802
김윤경ㆍ이민경 :Triptolide 와 L-NAME 의악관절통증조절효과 2. L-NAME의측두하악관절통증조절효과포르말린으로유도된측두하악관절통증모델에서 L-NAME 의소뇌연수조투여로인한통증조절효과는다음과같다. 1차통증행위반응의결과, 소뇌연수조내로 L-NAME (0.01, 0.1 g/10 l) 투여후포르말린을주입한군은각농도에따라 13.70±11.43회, 5.80±3.75회로통증행위반응을관찰하였고, 25.4±6.59회로나타난포르말린주입군과비교하였을때유의한차이를나타내었다. 2차통증행위반응에서는소뇌연수조내로 L-NAME 투여후포르말린을주입한군에서각농도에따라 219.50±59.76회, 92.30±16.04회의통증행위반응의변화를관찰하였으며, 0.1 g/10 l의 L-NAME 투여군에서측두하악관절통증조절효과가유의하게나타 Fig. 3. Effects of L-NAME on temporomandibular joint (TMJ) nociceptive behavior. The nociceptive responses were reduced in 1st phase (0 10 min) and 2nd phase (11 45 min) following intracisternal administration of L-NAME 10 min before formalin (F) injection into TMJ capsule (n=6). *p<0.05, F vs. L-NAME 0.1 g+f. 났다. 반면에 vehicle 군의 1, 2 차통증행위반응의결과, 각각 38.70±10.33회, 253.50±48.46회로나타나 vehicle은측두하악관절통증조절에영향을미치지않는다는것을알수있었다 (Fig. 3). 소뇌연수조내로 L-NAME (0.1 g/10 l) 투여후포르말린을주입한실험군의통증행위반응은포르말린주입후 20, 40분에유의하게통증행위반응이감소되었다 (Fig. 4). 3. Triptolide와 L-NAME의병용투여에의한측두하악관절통증조절효과포르말린으로유도된측두하악관절통증모델에서 triptolide 와 L-NAME의병용투여에의한측두하악관절통증조절효과는다음과같다. 그래프에나타내지는않았으나, 각각의농도에서통증조절효과를나타내지않았던 0.1 g/10 l의 triptolide와 0.01 g/10 l의 L-NAME의병용투여군은유의한측두하악관절통증조절효과를나타내지않았다. 하지만 1 g/10 l의 triptolide와 0.01 g/10 l의 L-NAME 병용투여군에서 1차통증행위반응은 0.80±0.80회로나타나 1 g/10 l의 triptolide만주입한실험군 (22.50±19.15회) 과비교시유의하게감소함을확인하였다. 2차통증행위반응의결과에서도병용투여군은 96.50±26.16회로 triptolide 군 (163.33±29.11회) 과비교시통증행위반응이유의하게감소되었음을확인하였다. 결과적으로, 통증조절효과를나타내지않았던저농도의 L-NAME는 triptolide와병용투여시 triptolide 단독투여와비교하여측두하악관절통증경감효과를증가시킬수있음을확인하였다 (Fig. 5). 통증행위반응의시간의경과에따라 triptolide와 L-NAME의소뇌연수 Fig. 4. Changes in nociceptive responses following intracisternal administration of L-NAME. The administration of L-NAME into temporomandibular joint (TMJ) capsule reduced the nociceptive responses 20, 40 min after induction of TMJ pain. *p<0.05, formalin (F) vs. L-NAME 0.1 g+f. Fig. 5. Combined effect of triptolide (T) and L-NAME on temporomandibular joint (TMJ) nociceptive behavior. The nociceptive responses were reduced in 1st phase (0~10 min) and 2nd phase (11~45 min) following intracisternal administration of T and L-NAME 10 min before formalin (F) injection into TMJ capsule (n=6). *p<0.05, T 1 g+f vs. T 1 g+l-name 0.01 g+f. 803
J Dent Hyg Sci Vol. 15, No. 6, 2015 Fig. 6. Changes in nociceptive responses following intracisternal co-administration of triptolide (T) and L-NAME. Co-administration of both drugs into temporomandibular joint (TMJ) capsule reduced the nociceptive responses 10 min after induction of TMJ pain. *p<0.05, T 1 g+formalin (F) vs. T 1 g+l-name 0.01 g+f. 조병용투여군은포르말린을주입후 10분에통증행위반응이가장유의하게감소되었음을확인하였다 (Fig. 6). 고찰 이번연구는포르말린으로유도된실험동물의측두하악관절통증모델에서 triptolide와 L-NAME의소뇌연수조내로각각의단독투여가측두하악관절통증조절에관여하는지평가하고, 약물의치료효과를높이면서그사용량을줄이기위한방법으로 triptolide와 L-NAME의병용투여가통증조절에미치는영향을평가하고자하였다. 선행연구에서, triptolide의척수강내투여는유선암종세포를경골골수강에주입하여유도한골암통증모델에서실험동물의뒷발바닥에증가된기계적통각 9) 과척수신경결찰에의해증가된기계적이질통 10) 을완화시켰다고보고되었다. 이와마찬가지로, 이번연구의결과에서도 triptolide (1 g/10 l) 의소뇌연수조투여는측두하악관절강내주입한포르말린으로유도된측두하악관절통증행위반응을유의하게감소시켜통증조절효과를나타내었다. 이러한 triptolide의통증행위의경감효과는염증성통증신호의전달과정을조절함으로써나타나는것으로생각된다. Triptolide의염증성통증신호의전달물질과관련한연구들에서, 신경결찰에따라증가된 tumor necrosis factor- (TNF- ), IL-2는 triptolide의척수강내투여로인해억제되었고 9), 척수신경결찰에의한신경병증성통증모델에서 triptolide의복강투여는기계적이질통과함께증가된염증성매개물인 IL-6, IL-1, monocyte chemotactic TNF- 의 mrna의발현을억제하였다고 8) 보고하였다. 이러한 triptolide 의통증신호의조절효과는이번연구결과에서나타난 triptolide의통증경감효과를뒷받침한다. Jung 등 16) 의보고에따르면, 포르말린으로유도된안면부통증행위반응은 L-NAME의소뇌연수조투여로감소되었고, Hwang 등 21) 은 CFA에의해유도된염증성통증모델에서쥐의뒤뿌리신경절내신경세포는통증에의해 NO를증가시키고 L-NAME의후처치로통증경감과함께감소되었다고보고하였다. 이와마찬가지로이번연구에서, 0.1 g/ 10 l의 L-NAME 소뇌연수조투여군은포르말린으로유도된측두하악관절통증행위반응을감소시켰고, 이러한결과는 L-NAME 소뇌연수조투여가통증전달및감지에서중요한역할을하는 NO의합성을억제함으로써측두하악관절통증조절효과를나타낸것으로생각된다. Triptolide의 NO 조절에관한연구에서, triptolide는 NO 의합성효소인 inos를억제하고 adjuvant arthritis에의한실험동물의열성이질통을감소시켰다고하였고 22), in vivo 실험에서 23) triptolide는 NO의생성과 inos의발현을억제하여염증을조절하였다고보고하였다. 이러한연구결과는 triptolide의투여가 NO의생성과관련된통증기전에연관이있으며 L-NAME와 triptolide의병용투여시긍정적인상호작용의가능성을제시한다. 이를확인하기위한이번연구의실험에서 1 g/10 l의 triptolide와 0.01 g/10 l의 L-NAME 병용투여군은 1 g/10 l의 triptolide 단독투여군과비교시통증행위반응이유의하게감소되어나타났다. 이는두약물의상호작용에의해통증조절효과를나타내지않았던저용량의 L-NAME가 triptolide의통증조절효과를강화시킨것으로생각된다. 하지만 L-NAME와 triptolide의병용투여가통증신호의전달과정에서어떠한생리약리학적경로를통해상호작용을나타내는지에대한연구가이루어지지않아추후추가적으로더많은연구가필요할것으로생각된다. 이상의결과를종합하며, triptolide와 L-NAME의소뇌연수조투여는포르말린에의해유도된측두하악관절통증행위반응을각각감소시켰으며, 두약물의병용투여시진통효과를나타내지않은저용량의 L-NAME는 triptolide의통증조절효과를강화시켰다. 이러한연구결과는측두하악관절통증경감을위한천연물의개발에 triptolide가새로운치료제로제시될수있으며, 천연물과화합물들의병용투여를통한상호작용으로그효과를증가시킬수있을것으로생각된다. 804
김윤경ㆍ이민경 :Triptolide 와 L-NAME 의악관절통증조절효과 요약 이연구는 triptolide와 L-NAME의측두하악관절통증조절효과를확인하기위하여포르말린으로유도된측두하악관절통증모델에서 triptolide와 L-NAME의소뇌연수조내각각의얄물의단독투여에따른통증행위반응과두약물의병용투여에따른상호작용이통증행위반응에미치는영향을평가하여다음과같은결과를얻었다. 먼저, 관절강내로주입한 5% 포르말린 (30 l) 은유의한통증행위반응을유발하였고, 2차통증행위반응관찰시포르말린주입전 1 g/ 10 l triptolide 투여군 (163.33±29.11회) 은포르말린군 (308± 33.04회 ) 과비교시통증행위반응이유의하게감소하였다. 0.1 g/10 l의 L-NAME 투여군의 1, 2차통증행위반응의결과, 각각 5.80±3.75회, 92.30±16.04회로포르말린주입군 25.4±6.59회, 285.60±29.93회와비교시유의하게감소되었다. 다음으로, 1 g/10 l의 triptolide와 0.01 g/10 l 의 L-NAME 병용투여군에서 1, 2차통증행위반응이 0.80± 0.80회, 96.50±26.16회로나타나 22.50±19.15회, 163.33± 29.11회로나타난 1 g/10 l trtiptolide군과비교시유의하게통증행위반응이경감되었다. 이러한연구결과는측두하악관절통증조절의예방및치료에있어활용가능한천연물로 triptolide가제시될수있으며, 천연물과화합물들의병용투여를통해그효과를증가시킬수있을것으로기대된다. 감사의글 이논문은 2014년도동의대학교연구비지원 (2015AA002) 에의하여수행된결과로이에감사드립니다. References 1. Won KA, Lim NH, Lee MK, et al.: A blockade of the central MAPK pathway attenuates referred pain in rats with complete freund's adjuvant-induced inflammation of the temporomandibular joint. Int J Oral Biol 35: 83-89, 2010. 2. Choe JR, Song CW: The study for treatment of temporomandibular joint pain. J Korean Pain Soc 8: 86-92, 1995. 3. Im YG, Baek HS, Kim BG: Correspondence between temporomandibular disorder symptoms and clinical examination findings. J Oral Med Pain 35: 83-91, 2010. 4. Dworkin SF, Huggins KH, LeResche L, et al.: Epidemiology of signs and symptoms in temporomandibular disorders: clinical signs in cases and controls. J Am Dent Assoc 120: 273-281, 1990. 5. Kim JY, Han KS, Jung DY, Lee SC: Predicting factors for the treatment outcome of intracapsular pain of the temporomandibular disorders. J Oral Med Pain Assoc 27: 77-87, 2002 6. Barretto SR, de Melo GC, dos Santos JC, et al.: Evaluation of anti-nociceptive and anti-inflammatory activity of low-level laser therapy on temporomandibular joint inflammation in rodents. J Photochem Photobiol B 129: 135-142. 2013. 7.Kim YK, Hyun KA, Lee MK: Anti-inflammatory and antioxidative antioxidative effects of acaiberry in formalininduced orofacial pain in rats. J Dent Hyg Sci 14: 240-247, 2014. 8. Wang W, Mei XP, Chen L, et al.: Triptolide prevents and attenuates neuropathic pain via inhibiting central immune response. Pain Physician 15: E995-1006, 2012. 9. Hu JY, Li CL, Wang YW: Intrathecal administration of triptolide, a T lymphocyte inhibitor, attenuates chronic constriction injury-induced neuropathic pain in rats. Brain Res 1436: 122-129, 2012. 10. Hang LH, Li SN, Shao DH, Chen Z, Chen YF, Shu WW: Evidence for involvement of spinal RANTES in the antinociceptive effects of triptolide, a diterpene triepoxide, in a rat model of bone cancer pain. Basic Clin Pharmacol Toxicol 115: 477-480, 2014. 11. Xu F, Li Y, Li S, et al.: Complete Freund's adjuvant-induced acute inflammatory pain could be attenuated by triptolide via inhibiting spinal glia activation in rats. J Surg Res 188: 174-182, 2014. 12. Gao ZW, Wang DZ, Liu BL, Ma HH: Expression of inducible nitric oxide synthase in cartilage in progression of temporomandibular joint osteoarthritis. Hua Xi Kou Qiang Yi Xue Za Zhi 25: 216-218, 2007. 13. Jeon YT, Seo KS, Ro YJ, et al.: The role of nitric oxide synthase isoforms in neuropathic pain induced by nerve injury in rats. Korean J Anesthesiol 48: 76-84, 2004. 14. Kim MK, Choi Y, Kong HS, et al.: Effects of L-NAME on the mechanical hyperalgesia after the development of inflammation by freund's complete adjuvant in rat paw. J Korean Pain Soc 12: 171-176, 1999. 15. Kang YM, Lee MK, Yang GY, Bae YC, Ahn DK: Participation of nitric oxide pathways in interleukin 1-induced mechanical allodynia in the orofacial area of rats. Int J Oral Bio 34: 1-6, 2009. 805
J Dent Hyg Sci Vol. 15, No. 6, 2015 16. Jung HS, Jeon, HB, Jeon IS, et al.: Preventing extracellular diffusion of trigeminal nitric oxide enhances formalin- induced orofacial pain. Korean J Physiol Pharmacol 13: 379-383, 2009. 17. Han DW, Kweon TD, Lee JS, Yoo YC, Lee YW, Kim SC: The interaction between intrathecal NMDA receptor antagonist and 5-HT3 receptor agonist in the rat formalin test. Korean J Anesthesiol 52: 694-701, 2007. 18. Shim JH, Jun JH, Kim KH, Yeom JH, Suh JK: The analgesic interactions among intrathecal morphine, ketorolac and L-NAME on formalin-induced pain in rats. Korean J Anesthesiol 43: 780-790, 2002. 19. Yang GY, Lee JH, Ahn DK: Participation of NMDA and non-nmda glutamate receptors in the formalin-induced inflammatory temporomandibular joint nociception. Int J Oral Bio 32: 59-65, 2007. 20. Kim YK, Choi JH, Lee HJ, et al.: Analgesic effects of triptolide via peripheral and central administration in rat model of inflammatory orofacial pain. J Dent Hyg Sci 15: 424-429, 2015. 21. Hwang SJ, Lee JH, Chung TJ, et al.: A change of nitric oxide in rat drg following freund's complete adjuvant induced inflammtory pain. Korean J Anat 33: 135-142, 2000. 22. Chen W, Zhang XD, Lu ZH, Wei DM: Effect of triptolide on inos and SP expressions in spinal dorsal horn and dorsal root ganglion of rats with adjuvant arthritis. Zhongguo Zhong Yao Za Zhi 39: 1675-1679, 2014. 23. Kim YH, Lee SH, Lee JY, Choi SW, Park JW, Kwon TK: Triptolide inhibits murine-inducible nitric oxide synthase expression by down-regulating lipopolysaccharide-induced activity of nuclear factor-kappa B and c-jun NH2-terminal kinase. Eur J Pharmacol 494: 1-9, 2004. 806