Electroacupuncture (EA) has been used for treating visceral hypersensitivity (VH). However, the underlying molecular mechanism remains unclear. This study was aim to testify the effect of EA on ileitis-provoked VH, and to confirm whether EA attenuates VH through Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) signaling pathway in the periaqueductal gray (PAG)-the rostral ventromedial medulla (RVM)-the spinal cord dorsal horn (SCDH) axis. Methods: Goats were anesthetized and laparotomized for injecting 2,4,6-trinitro-benzene-sulfonic acid (TNBS)-ethanol solution (30mg TNBS dissolved in 40% ethanol) into the ileal wall to induce VH. EA was treated for 30min from day 7, then every 3 days for six times. VH was assessed by visceromotor response (VMR) and pain behavior response to 20, 40, 60, 80, and 100 mmHg colorectal distension pressures at day 7, 10, 13, 16, 19, and 22. The spinal cord in the eleventh thoracic vertebra and the brain were collected at day 22. The protein and mRNA levels of IL-6, JAK2, and STAT3 in the SCDH were detected with western blot and qPCR, respectively. The distribution of these substances was observed with immunohistochemistry in the ventrolateral PAG (vlPAG), RVM (mainly the nucleus raphe magnus, NRM), SCDH, the nucleus tractus solitaries (NTS) and the dorsal motor nucleus of vagi (DMV). Results: Goats administered with TNBS-ethanol solution showed diarrhea, enhanced VMR and pain behavior response, and increased IL-6, phosphorylated JAK2 and STAT3 (pJAK2 and pSTAT3) in the vlPAG, NRM, NTS and DMV, and their protein and mRNA levels in the SCDH. EA relieved diarrhea, VMR and pain behavior response, decreased IL-6, pJAK2 and pSTAT3 levels in the vlPAG, NRM, SCDH, NTS, and DMV except for pSTAT3 in the DMV, but did not affect mRNA level of these three substances in the SCDH. Conclusion: EA attenuates VH probably through inhibiting JAK2/STAT3 signaling pathway in the PAG-RVM-SCDH axis.

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.

Electroacupuncture (EA) relieves visceral hypersensitivity (VH) with underlying inflammatory bowel diseases. However, the mechanism by which EA treats ileitis-induced VH is not clearly known. To assess the effects of EA on ileitis-induced VH and confirm whether EA attenuates VH through spinal PAR-2 activation and CGRP release, goats received an injection of 2,4,6-trinitro-benzenesulfonic-acid (TNBS) solution into the ileal wall. TNBS-injected goats were allocated into VH, Sham acupuncture (Sham-A) and EA groups, while goats treated with saline instead of TNBS solution were used as the control. Goats in EA group received EA at bilateral Hou-San-Li acupoints for 0.5 h at 7 days and thereafter repeated every 3 days for 6 times. Goats in the Sham-A group were inserted with needles for 0.5 h at the aforementioned acupoints without any hand manipulation and electric stimulation. Visceromotor responses to colorectal distension, an indicator of VH, were recorded by electromyography. The terminal ileum and thoracic spinal cord (T₁₁) were sampled for evaluating ileitis at days 7 and 22, and distribution and expression-levels of PAR-2, CGRP and c-Fos on day 22. TNBS-treated-goats exhibited apparent transmural-ileitis on day 7, microscopically low-grade ileitis on day 22 and VH at days 7–22. Goats of Sham-A, VH or EA group showed higher (P < 0.01) VH at days 7–22 than the Control-goats. EA-treated goats exhibited lower (P < 0.01) VH as compared with Sham-A or VH group. Immunoreactive-cells and expression-levels of spinal PAR-2, CGRP and c-Fos in the EA group were greater (P < 0.01) than those in the Control group, but less (P < 0.01) than those in Sham-A and VH groups on day 22. Downregulation of spinal PAR-2 and CGRP levels by EA attenuates the ileitis and resultant VH.

Background and Aims: Crohn’s Disease (CD), a chronic Inflammatory Bowel Disease, can occur in any part of the gastrointestinal tract, but most frequently in the ileum. Visceral hypersensitivity contributes for development of chronic abdominal pain in this disease. Currently, the understanding of the mechanism underlying hypersensitivity of Crohn’s ileitis has been hindered by a lack of specific animal model. The present study is undertaken to investigate the visceral hypersensitivity provoked by 2,4,6-trinitrobenzene sulfonic (TNBS)-induced ileitis rats. Methods: Male Sprague-Dawley rats were anaesthetized and laparotomized for intraileal injection of TNBS (0.6 ml, 80 mg/kg body weight in 30% ethanol, n = 48), an equal volume of 30% Ethanol (n = 24) and Saline (n = 24), respectively. Visceral hypersensitivity was assessed by visceromotor responses (VMR) to 20, 40, 60, 80 and 100 mmHg colorectal distension pressure (CRD) at day 1, 3, 7, 14, 21 and 28. Immediately after CRD test, the rats were euthanized for collecting the terminal ileal segment for histopathological examinations and ELISA of myleoperoxidase and cytokines (TNF-α, IL-1β, IL-6), and dorsal root ganglia (T11) for determination of calcitonin gene-related peptide by immunohistochemistry, respectively. Results: Among all groups, TNBS-treatment showed transmural inflammation initially at 3 days, reached maximum at 7 days and persisted up to 21 days. The rats with ileitis exhibited (P < 0.05) VMR to CRD at day 7 to day 21. The calcitonin gene-related peptide-immunoreactive positive cells increased (P < 0.05) in dorsal root ganglia at day 7 to 21, which was persistently consistent with visceral hypersensitivity in TNBS-treated rats. Conclusions: TNBS injection into the ileum induced transmural ileitis including granuloma and visceral hypersensitivity. As this model mimics clinical manifestations of CD, it may provide a road map to probe the pathogenesis of gut inflammation and visceral hypersensitivity, as well as for establishing the therapeutic protocol for Crohn’s ileitis.

Background: Visceral hypersensitivity (VH) is a common condition in many gastrointestinal disorders such as inflammatory bowel diseases (IBDs) in human and animals. Most studies often induce Crohn’s disease/colitis to investigate VH in small experimental animals. Although farm animals commonly suffer from IBDs, their VH has not been investigated so far. Because goats can suffer from Johne’s disease, a naturally occurring Crohn’s-like disease, they may be suitable to be used for studying the mechanism underlying VH in common intestinal disorders of large animals. In the present study, 60 healthy goats of either sex were equally divided into a 2, 4, 6-trinitrobenzenesulfonic acid (TNBS) group and saline group. A volume of 1.2 ml of TNBS-ethanol solution (30 mg TNBS in 40 % ethanol) or an equal volume of isotonic saline was injected into the wall of the terminal ileum through laparotomy. The severity of the developing ileitis was determined according to macro- and microscopic pathologic scores and the levels of myeloperoxidase, interleukin-1β, interleukin-6 and tumor necrosis factor-α, and VH was evaluated with visceromotor responses (VMR) to colorectal distension on days 3, 7, 14, 21 and 28. VMRs were assessed with a continuous ramp distention mode with 6 s for each pressure (20, 40, 60, 80 and 100 mmHg). Results: Compared to the saline group, the TNBS-treated goats showed apparent transmural pathological changes and a significant increase ( P < 0.05) in macroscopic and microscopic change scores, and levels of myeloperoxidase, interleukin-1β, interleukin-6 and tumor necrosis factor-α in the ileum, and VMR to colorectal distension. The goats exhibited apparent ileitis at days 3 to 21, and VH at days 7 to 28 following TNBS treatment. Conclusion: This experiment successfully established a reproducible ileitis and VH with administration of TNBS-ethanol solution in the ileal wall of goats. This model is useful for studying the pathogenesis of the IBD and the mechanism underlying VH, and for evaluating the efficacy of new therapeutic regimens.

Induced molting of laying hens is a common husbandry practiced in many commercial farms. This study was aimed to evaluate the effectiveness of induced molting on production parameters along with production economics of Layers. For this study, Lohmann Brown-Classic hens were reared in a modern cage system from 10 weeks of age. There was no significant difference(P>0.05) in egg production in Hen Day Basis (HDP) before 65 weeks in comparison to standard performance table provided by Lohmann Brown- Classic Layers Management Guide (Cage Housing). A total of 8087 laying hens were divided into two treatment groups after 65 weeks of age; one group (N=4055) without any feed restriction (control=T0) and another (N=4032) had induced molting with 15 days of feed restriction, provided with only water and mineral supplements (T1) followed by five days of exclusive Ground Maize feeding. The average HDP before division of treatment was recorded 83.37%. The T0 and T1 group were reared up to 85 and 109 weeks respectively, in accordance to the economical sustainability. The feed intake per bird, egg production including marketable and non-marketable eggs and mortality along with production economics of both groups were recorded. The T1 group reached its peak egg production (88.48%) on Hen Day Basis (HDP) after 62 days following treatment which was higher (P<0.05) than the T0 group. The ratio of marketable to non-marketable eggs was found higher in T1 (69.32:1) than that of T0 (38.53:1). The production cost per egg was recorded NRs.6.86 and 6.99 respectively for T1 and T0 group with 4.33% more profit on T1 than T0 group. This study suggests that induced molting with feed restriction approach is beneficial to bypass the scarcity period with falling market value of eggs and also increase the ratio of marketable eggs to non-marketable eggs. Int. J. Appl. Sci. Biotechnol. Vol 7(4): 429-433