Chronic pancreatitis affects many individuals around the world,and the study of the underlying mechanisms leading to better treatment possibilities are important tasks.Therefore,animal models are needed to illustrate ...Chronic pancreatitis affects many individuals around the world,and the study of the underlying mechanisms leading to better treatment possibilities are important tasks.Therefore,animal models are needed to illustrate the basic study of pancreatitis.Recently,animal models of acute and chronic pancreatitis have been thoroughly reviewed,but few reviews address the important aspect on the translation of animal studies to human studies.It is well known that pancreatitis is associated with epigastric pain,but the understanding regarding to mechanisms and appropriate treatment of this pain is still unclear.Using animal models to study pancreatitis associated visceral pain is difficult,however,these types of models are a unique way to reveal the mechanisms behind pancreatitis associated visceral pain.In this review,the animal models of acute,chronic and un-common pancreatitis are briefly outlined and animal models related to pancreatitis associated visceral pain are also addressed.展开更多
Acute pain,provoked generally after the activation of peripheral nociceptors,is an adaptive sensory function that alerts the individual to avoid noxious stimuli.However,uncontrolled acute pain has a maladaptive role i...Acute pain,provoked generally after the activation of peripheral nociceptors,is an adaptive sensory function that alerts the individual to avoid noxious stimuli.However,uncontrolled acute pain has a maladaptive role in sensory activity leading to development of a chronic pain state which persists even after the damage is resolved,or in some cases,in the absence of an initial local acute injury.Huge numbers of people suffer from visceral pain at least once during their life span,leading to substantial health care costs.Although studies reporting on the mechanism of visceral pain are accumulating,it is still not precisely understood.Therefore,this review aims to elucidate the mechanism of visceral pain through an evaluation of different animal models and their application to develop novel therapeutic approaches for treating visceral pain.To assess the nociceptive responses in viscera,several visceral pain models such as inflammatory,traction,stress and genetic models utilizing different methods of measurement have been devised.Among them,the inflammatory and traction models are widely used for studying the visceral pain mechanism of different disease conditions and post-operative surgery in humans and animals.A hapten,2,4,6-trinitrobenzene sulfonic acid(TNBS),has been extensively used as an inflammatory agent to induce visceral pain.The traction model seems to cause a strong pain stimulation and autonomic reaction and could thus be the most appropriate model for studying the underlying visceral pain mechanism and for probing the therapeutic efficacies of various anesthetic and analgesics for the treatment of visceral pain and hyperalgesia.展开更多
Objective · Formalin is a classic and most widely used algogenic substance, but its itchy effect is not clear. The present study aims to explore the hypothesis that formalin may induce itch as well as pain. Metho...Objective · Formalin is a classic and most widely used algogenic substance, but its itchy effect is not clear. The present study aims to explore the hypothesis that formalin may induce itch as well as pain. Methods · Flinching, as well as licking and forelimb wiping of the site of injection were counted as pain responses, whereas biting and hind paw scratching of the cheek were counted as itchy responses. To discriminate formalin-induced sensations in rats, the irritant(saline as control) was injected, and then pain and itchy responses were recorded.Results · Intraplantar injection of formalin elicited biphasic behavior responses characterized as flinching, as well as biting or licking of the hind paw without significant gender differences. Following intradermal administration of formalin to the cheek, rats exhibited episodic forelimb wiping of the cheek, representative of pain. No gender difference was noticed for this type of behavior. In addition, episodes of hind paw scratches of the cheek, representative of pruritoceptive responses, also occurred. Interestingly, hind paw scratches appeared to be more pronounced in male than in female rats. Conclusion · Intradermal administration of formalin elicits pruritoceptive as well as nociceptive responses in rats.展开更多
A rat model of extra-vertebral foramen cervical nerve entrapment was established according to the following parameters： stimulation intensity 20 V; frequency 50 Hz; pulse width 200 μs; duration 333 ms/s for a total ...A rat model of extra-vertebral foramen cervical nerve entrapment was established according to the following parameters： stimulation intensity 20 V; frequency 50 Hz; pulse width 200 μs; duration 333 ms/s for a total of 8 hours. After the electrical stimulation, rats exhibited mild muscle fiber atrophy, mild inflammatory exudates, connective tissue local fibrosis and chondrocyte metaplasia. Mean muscle fiber cross-sectional area was reduced. The nerve myelin sheath continuity was partially demyelinated. The microstructure of nerve cells was disrupted and these symptoms worsened with prolongation of the stimulation. The shoulder, neck and upper extremity muscles on the tested side demonstrated positive sharp waves and fibrillations. The severity increased with continuation of the stimulation. High amplitude and polyphasic motor unit potentials gradually appeared. Similar findings were seen in the contralateral side, but at a less severe level.展开更多
AIM:Irritable bowel syndrome(IBS)is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel motility.There is increasing evidence suggesting the role of inflammation in the pathogenesi...AIM:Irritable bowel syndrome(IBS)is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel motility.There is increasing evidence suggesting the role of inflammation in the pathogenesis of IBS,which addresses the possibility that formerly established rat model of colitis could be used as an IBS model after the inflammation subsided. METHODS:Colitis was induced by intracolonic instillation of 4% acetic acid in male Sprague-Dawley rats.The extent of inflammation was assessed by histological examination and myeloperoxidase(MPO)activity assay.After subsidence of colitis,the rats were subjected to rectal distension and restraint stress,then the abdominal withdrawal reflex and the number of stress-induced fecal output were measured, respectively. RESULTS:At 2 days post-induction of colitis,the colon showed characteristic inflammatory changes in histology and 8-fold increase in MPO activity.At 7 days post-induction of colitis,the histological features and MPO activity returned to normal.The rats at 7 days post-induction of colitis showed hypersensitive response to rectal distension without an accompaning change in rectal compliance,and defecated more stools than control animals when under stress.CONCLUSION: These results concur largely with the characteristic features of IBS, visceral hypersensitivity and altered defecation pattern in the absence of detectable disease, suggesting that this animal model is a methodologically convenient and useful model for studying a subset of IBS.展开更多
Objective To evaluate the use of the saphenous artery as an alternative access for endovascular procedures in the porcine model. Methods Fourteen adult pigs (25-35 kg) were used in this study, 3 pigs from an acute stu...Objective To evaluate the use of the saphenous artery as an alternative access for endovascular procedures in the porcine model. Methods Fourteen adult pigs (25-35 kg) were used in this study, 3 pigs from an acute study and 11 from chronic studies. A 2-3 cm incision was made and a saphenous artery cutdown was performed in 24 sides. Micropuncture sets (Boston Scientific) or 18 G puncture needles were used to access the artery. Different sizes of introducers (4-7 F) were used to establish endovascular access. Angiographic catheters were then used to confirm if the access was usable. Four saphenous arteries were explanted in the pigs from a chronic study 4 to 28 days after surgical procedure. Results The saphenous artery was very easy to expose and 4-5 F introducer sheaths were able to be inserted to establish access for endovascular procedures in the pigs. The saphenous artery was unable to accomodate an introducer with a size larger than 6 F. Four saphenous arteries were injured when 5 and 6 F introducers were used, but angiographic procedures could still be performed. Morphologic evaluation of the explanted arteries demonstrated occlusion of the saphenous arteries without injury or disruption of the adjacent femoral arteries. Conclusion The saphenous artery can be used as an access site in pigs for angiographic and interventional procedures if the catheter size is less than 6 F. This vessel is easier to access and can preserve the femoral artery for repeat procedures in the future.展开更多
文摘Chronic pancreatitis affects many individuals around the world,and the study of the underlying mechanisms leading to better treatment possibilities are important tasks.Therefore,animal models are needed to illustrate the basic study of pancreatitis.Recently,animal models of acute and chronic pancreatitis have been thoroughly reviewed,but few reviews address the important aspect on the translation of animal studies to human studies.It is well known that pancreatitis is associated with epigastric pain,but the understanding regarding to mechanisms and appropriate treatment of this pain is still unclear.Using animal models to study pancreatitis associated visceral pain is difficult,however,these types of models are a unique way to reveal the mechanisms behind pancreatitis associated visceral pain.In this review,the animal models of acute,chronic and un-common pancreatitis are briefly outlined and animal models related to pancreatitis associated visceral pain are also addressed.
文摘Acute pain,provoked generally after the activation of peripheral nociceptors,is an adaptive sensory function that alerts the individual to avoid noxious stimuli.However,uncontrolled acute pain has a maladaptive role in sensory activity leading to development of a chronic pain state which persists even after the damage is resolved,or in some cases,in the absence of an initial local acute injury.Huge numbers of people suffer from visceral pain at least once during their life span,leading to substantial health care costs.Although studies reporting on the mechanism of visceral pain are accumulating,it is still not precisely understood.Therefore,this review aims to elucidate the mechanism of visceral pain through an evaluation of different animal models and their application to develop novel therapeutic approaches for treating visceral pain.To assess the nociceptive responses in viscera,several visceral pain models such as inflammatory,traction,stress and genetic models utilizing different methods of measurement have been devised.Among them,the inflammatory and traction models are widely used for studying the visceral pain mechanism of different disease conditions and post-operative surgery in humans and animals.A hapten,2,4,6-trinitrobenzene sulfonic acid(TNBS),has been extensively used as an inflammatory agent to induce visceral pain.The traction model seems to cause a strong pain stimulation and autonomic reaction and could thus be the most appropriate model for studying the underlying visceral pain mechanism and for probing the therapeutic efficacies of various anesthetic and analgesics for the treatment of visceral pain and hyperalgesia.
文摘Objective · Formalin is a classic and most widely used algogenic substance, but its itchy effect is not clear. The present study aims to explore the hypothesis that formalin may induce itch as well as pain. Methods · Flinching, as well as licking and forelimb wiping of the site of injection were counted as pain responses, whereas biting and hind paw scratching of the cheek were counted as itchy responses. To discriminate formalin-induced sensations in rats, the irritant(saline as control) was injected, and then pain and itchy responses were recorded.Results · Intraplantar injection of formalin elicited biphasic behavior responses characterized as flinching, as well as biting or licking of the hind paw without significant gender differences. Following intradermal administration of formalin to the cheek, rats exhibited episodic forelimb wiping of the cheek, representative of pain. No gender difference was noticed for this type of behavior. In addition, episodes of hind paw scratches of the cheek, representative of pruritoceptive responses, also occurred. Interestingly, hind paw scratches appeared to be more pronounced in male than in female rats. Conclusion · Intradermal administration of formalin elicits pruritoceptive as well as nociceptive responses in rats.
基金the National Natural Science Foundation of China,No. 81171707the Major State Basic Research Program of China,No.2012CB933600+2 种基金Shanghai Pujiang Program,No.11PJD016China Postdoctoral Science Foundation,No. 20090460629Fund for Key Disciplines of Shanghai Municipal Education Commission,No.J50206
文摘A rat model of extra-vertebral foramen cervical nerve entrapment was established according to the following parameters： stimulation intensity 20 V; frequency 50 Hz; pulse width 200 μs; duration 333 ms/s for a total of 8 hours. After the electrical stimulation, rats exhibited mild muscle fiber atrophy, mild inflammatory exudates, connective tissue local fibrosis and chondrocyte metaplasia. Mean muscle fiber cross-sectional area was reduced. The nerve myelin sheath continuity was partially demyelinated. The microstructure of nerve cells was disrupted and these symptoms worsened with prolongation of the stimulation. The shoulder, neck and upper extremity muscles on the tested side demonstrated positive sharp waves and fibrillations. The severity increased with continuation of the stimulation. High amplitude and polyphasic motor unit potentials gradually appeared. Similar findings were seen in the contralateral side, but at a less severe level.
基金the Research Institute of Veterinary Science,College of Veterinary Medieine,Seoul National University
文摘AIM:Irritable bowel syndrome(IBS)is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel motility.There is increasing evidence suggesting the role of inflammation in the pathogenesis of IBS,which addresses the possibility that formerly established rat model of colitis could be used as an IBS model after the inflammation subsided. METHODS:Colitis was induced by intracolonic instillation of 4% acetic acid in male Sprague-Dawley rats.The extent of inflammation was assessed by histological examination and myeloperoxidase(MPO)activity assay.After subsidence of colitis,the rats were subjected to rectal distension and restraint stress,then the abdominal withdrawal reflex and the number of stress-induced fecal output were measured, respectively. RESULTS:At 2 days post-induction of colitis,the colon showed characteristic inflammatory changes in histology and 8-fold increase in MPO activity.At 7 days post-induction of colitis,the histological features and MPO activity returned to normal.The rats at 7 days post-induction of colitis showed hypersensitive response to rectal distension without an accompaning change in rectal compliance,and defecated more stools than control animals when under stress.CONCLUSION: These results concur largely with the characteristic features of IBS, visceral hypersensitivity and altered defecation pattern in the absence of detectable disease, suggesting that this animal model is a methodologically convenient and useful model for studying a subset of IBS.
文摘Objective To evaluate the use of the saphenous artery as an alternative access for endovascular procedures in the porcine model. Methods Fourteen adult pigs (25-35 kg) were used in this study, 3 pigs from an acute study and 11 from chronic studies. A 2-3 cm incision was made and a saphenous artery cutdown was performed in 24 sides. Micropuncture sets (Boston Scientific) or 18 G puncture needles were used to access the artery. Different sizes of introducers (4-7 F) were used to establish endovascular access. Angiographic catheters were then used to confirm if the access was usable. Four saphenous arteries were explanted in the pigs from a chronic study 4 to 28 days after surgical procedure. Results The saphenous artery was very easy to expose and 4-5 F introducer sheaths were able to be inserted to establish access for endovascular procedures in the pigs. The saphenous artery was unable to accomodate an introducer with a size larger than 6 F. Four saphenous arteries were injured when 5 and 6 F introducers were used, but angiographic procedures could still be performed. Morphologic evaluation of the explanted arteries demonstrated occlusion of the saphenous arteries without injury or disruption of the adjacent femoral arteries. Conclusion The saphenous artery can be used as an access site in pigs for angiographic and interventional procedures if the catheter size is less than 6 F. This vessel is easier to access and can preserve the femoral artery for repeat procedures in the future.
