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OBJECTIVE@#To observe the effect of blistering moxibustion on the expression levels of 5-hydroxytyptamine (5-HT) and its receptors of the colon tissue in the mice with visceral hypersensitivity of irritable bowel syndrome (IBS), so as to explore the effect mechanism of blistering moxibustion in treatment of IBS.@*METHODS@#Forty SPF-grade newborn Kunming mice were randomly divided into a normal group, a model group, an antagonist group and a blistering moxibustion group, 10 mice in each one. Before modeling, the injection with 0.2 mL parachlorophenylalanine (PCPA) was given on the lateral ventricle in the antagonist group. The endorectal glacial acetic acid stimulation combined with tail clipping was used to prepare the model of visceral hypersensitivity of IBS in the model group, the antagonist group and the blistering moxibustion group. After modeling, in the blistering moxibustion group, the intervention with blistering moxibustion was exerted at "Zhongwan" (CV 12), "Tianshu" (ST 25) and "Zusanli" (ST 36), once herbal irritant plaster at each acupoint, for 2 h each time, once a week, consecutively for 3 weeks. Abdominal withdrawal reflex (AWR) score and electromyographic (EMG) amplitude of abdominal muscles were adopted to evaluate the visceral hypersensitivity. HE staining was applied to observe the morphological changes in colon tissue, and immunohistochemistry was to determine the expression levels of 5-HT and its receptors.@*RESULTS@#Compared with the normal group, EMG amplitude of abdominal muscles was increased under 20, 40 mm Hg (1 mm Hg=0.133 kPa) in the model group (P<0.05), AWR scores and EMG amplitude of abdominal muscles under 60, 80 mm Hg were all increased in the model group (P<0.05). In comparison with the model group, EMG amplitude of abdominal muscles was reduced under 20 mm Hg in the blistering moxibustion group (P<0.05), AWR scores were increased under 40 mm Hg in both the blistering moxibustion group and the antagonist group (P<0.05); AWR scores and EMG amplitude of abdominal muscles under 60, 80 mm Hg were all reduced in both the blistering moxibustion group and the antagonist group (P<0.05). Compared with the normal group, in the model group, the mucosa was slightly disturbed, while, the moderate inflammatory cells were visible in the submucosa. In comparison with the model group, the inherent glands of mucosa were regular in shape and a small number of inflammatory cells were visible in both the blistering moxibustion group and the antagonist group. In comparison with the normal group, the average positive staining area percentage (APSAP) of 5-HT and 5-HT3R of the colon tissue was increased, while, APSAP of 5-HT4R was reduced in the model group (P<0.05). Compared with the model group, APSAP of 5-HT and 5-HT3R was reduced in both the blistering moxibustion group and the antagonist group (P<0.05).@*CONCLUSION@#Blistering moxibustion can relieve the visceral hypersensitivity of the mice with visceral hypersensitive IBS and the underlying mechanism is related to the regulation of the gut-brain axis mediated by 5-HT signaling pathway.
Subject(s)
Animals , Mice , Rats , Disease Models, Animal , Hypersensitivity , Irritable Bowel Syndrome/therapy , Moxibustion , Rats, Sprague-Dawley , Serotonin , Signal TransductionABSTRACT
ABSTRACT Objective: The aim of this study was to investigate the effects of acute physical and psychological stress and temporary central nucleus of the amygdala (CeA) block on stress-induced visceral hypersensitivity. Methods: Forty two male Wistar rats were used in this study. Animals were divided into 7 groups (n = 6); 1 - Control, 2 - physical stress, 3 - psychological stress, 4 - sham, 5 - lidocaine, 6 - lidocaine + physical stress and 7 - lidocaine + psychological stress. Stress induction was done using a communication box. Results: Abdominal withdrawal reflex (AWR) score was monitored one hour after stress exposure. AWR score significantly heightened at 20, 40 and 60 mmHg in the psychological stress group compared with control (p < 0.05), while, it was almost unchanged in other groups. This score was strikingly decreased at 20, 40 and 60 mmHg in lidocaine + psychological stress group compared with psychological stress with no tangible response on physical stress. Total stool weight was significantly increased in psychological stress group compared with control (0.72 ± 0.15, 0.1 ± 0.06 g) (p < 0.05), but it did not change in physical stress compared to control group (0.16 ± 0.12, 0.1 ± 0.06 g) (p < 0.05). Concomitant use of lidocaine with stress followed the same results in psychological groups (0.18 ± 0.2, 0.72 ± 0.15 g) (p < 0.05), while it did not have any effect on physical stress group (0.25 ± 0.1, 0.16 ± 0.12 g) (p < 0.05). Conclusions: Psychological stress could strongly affect visceral hypersensitivity. This effect is statistically comparable with physical stress. Temporary CeA block could also reduce visceral hypersensitivity post-acute psychological stress.
RESUMEN Objetivo: O objetivo desse estudo foi investigar os efeitos do estresse físico e psicológico agudo e bloqueio temporário do núcleo central da amídala (CeA) na hipersensibilidade visceral induzida por estresse. Métodos: Quarenta e dois ratos Wistar machos foram empregados nesse estudo. Os animais foram divididos em 7 grupos (n = 6): 1 - Controle, 2 - estresse físico, 3 - estresse psicológico, 4 - simulacro, 5 - lidocaína, 6 - lidocaína + estresse físico e 7 - lidocaína + estresse psicológico. A indução do estresse foi feita com o uso de uma caixa de comunicação. Resultados: O escore do reflexo de retirada abdominal (RRA) foi monitorado uma hora depois da exposição ao estresse. O escore RRA aumentou significativamente a 20, 40 e 60 mmHg no grupo de estresse psicológico versus controle (p < 0,05), enquanto que praticamente permaneceu inalterado nos demais grupos. Esse escore diminuiu drasticamente a 20, 40 e 60 mmHg no grupo de lidocaína + estresse psicológico versus estresse psicológico, sem resposta tangível no estresse físico. O peso total das fezes aumentou significativamente no grupo de estresse psicológico versus controle (0,72 ± 0,15, 0,1 ± 0,06 g) (p < 0,05), mas não houve mudança no grupo de estresse físico versus controle (0,16 ± 0,12, 0,1 ± 0,06 g) (p < 0,05). O uso simultâneo da lidocaína com o estresse acompanhou os mesmos resultados nos grupos psicológicos (0,18 ± 0,2, 0,72 ± 0,15 g) (p < 0,05), enquanto que não foi observado qualquer efeito no grupo de estresse físico (0,25 ± 0,1, 0,16 ± 0,12 g) (p < 0,05). Conclusões: O estresse psicológico pode afetar fortemente a hipersensibilidade visceral. Esse efeito é estatisticamente comparável com o estresse físico. Um bloqueio temporário do CeA também pode reduzir a hipersensibilidade visceral pós-estresse psicológico agudo.
Subject(s)
Animals , Rats , Stress, Psychological/complications , Viscera/physiopathology , Central Amygdaloid Nucleus/physiopathology , Hypersensitivity/physiopathology , Reflex, Abdominal/physiology , Rats, Wistar , Pain Perception/physiology , Central Amygdaloid Nucleus/metabolismABSTRACT
Objective To optimize the preparation of air bag materials for abdominal withdrawal reflex test.Methods To measure the diameters of different pressue-air bags by digital vernier caliper and X ray imaging.Using the pain threshold (3 points) as a criterion to test the pressure values of different air bags in the rats with corresponding visceral pain sensitivity.Results With the increasing pressure, the changes of the diameter of round latex balloon were uniform and gentle, and could meet the pressure range used in the experiment (20~80 mmHg).The threshold of visceral pain in rats was near the nociceptive stimulus value,and would not cause irreversible damage to the rat intestinal tract.Conclusions Air bag made from round latrex ballon is an ideal tool to be used in abdominal withdrawal reflex test in rats.
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Abdominal withdrawal reflex (AWR) test, which evaluates the behavioral response of animals through expanding the intestinal tract, is the most widely used method to assess animal's visceral sensitivity in recent years.However, as AWR experimental operation involves many factors, it''s hard to find a commonly recognized operating procedure.Through review of literature of AWR experimental measuring methods, this article summarizes the basic steps of AWR operation.Meanwhile, it scrutinizes the differences of various measuring methods in relevant factors, including expansion method and airbag method, with special operating suggestions to them.Hopefully, this article will provide an option to future researchers who will use this method to evaluate animal''s visceral sensitivity, and provide a necessary foundation for the standardization of the experimental operation.
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BACKGROUND/AIMS: Abnormal visceral sensitivity and disordered motility are common in patients with diabetes mellitus. The purpose of the present study was to investigate whether visceral sensation and bowel motility were altered in a rat model of type 2 diabetes mellitus accompanied by weight loss. METHODS: A type 2 diabetic rat model in adulthood was developed by administrating streptozotocin (STZ; 90 mg/kg, i.p.) to neonatal rats. Eight weeks after STZ administration, rats with blood glucose level of 200 mg/dL or higher were selected and used as diabetic group (n = 35) in this study. Abdominal withdrawal reflex and arterial pulse rate were measured to examine visceral nociception induced by colorectal distension (0.1-1.0 mL). The amplitude, frequency, and area under the curve (AUC) of spontaneous phasic contractions of colonic circular muscles were recorded in vitro to examine colonic motility. RESULTS: STZ-treated diabetic rats gained significantly less weight for 8 weeks than control (P < 0.01). Forty-eight percent of the diabetic rats showed enhanced visceral nociceptive response to colorectal distension. Diabetic rats did not differ from control rats in colorectal compliance. However, the frequency and AUC, not the amplitude, of colonic spontaneous contraction in vitro was significantly decreased in diabetic rats compared to control rats (P < 0.01 in frequency and P < 0.05 in AUC). CONCLUSIONS: These results demonstrate visceral hypersensitivity and colonic dysmotility in a rat model of type 2 diabetes mellitus accompanied by weight loss.