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. 2015 Dec 17:311:166-79.
doi: 10.1016/j.neuroscience.2015.10.028. Epub 2015 Oct 19.

Alcohol and high fat induced chronic pancreatitis: TRPV4 antagonist reduces hypersensitivity

L P Zhang  1 , R H Kline 4th  1 , G Deevska  1 , F Ma  1 , M Nikolova-Karakashian  1 , K N Westlund  2
Affiliations

Alcohol and high fat induced chronic pancreatitis: TRPV4 antagonist reduces hypersensitivity

L P Zhang et al. Neuroscience. .

Abstract

The pathogenesis of pain in chronic pancreatitis is poorly understood, and its treatment can be a major clinical challenge. Surgical and other invasive methods have variable outcomes that can be unsatisfactory. Therefore, there is a great need for further discovery of the pathogenesis of pancreatitis pain and new therapeutic targets. Human and animal studies indicate a critical role for oxidative stress and activation of transient receptor potential (TRP) cation channel subfamily members TRPV1 and TRPA1 on pancreatic nociceptors in sensitization mechanisms that result in pain. However, the in vivo role of transient receptor potential cation channel subfamily V member 4 (TRPV4) in chronic pancreatitis needs further evaluation. The present study characterized a rat alcohol/high fat diet (AHF)-induced chronic pancreatitis model with hypersensitivity, fibrotic pathology, and fat vacuolization consistent with the clinical syndrome. The rats with AHF-induced pancreatitis develop referred visceral pain-like behaviors, i.e. decreased hindpaw mechanical thresholds and shortened abdominal and hindpaw withdrawal latency to heat. In this study, oxidative stress was characterized as well as the role of TRPV4 in chronic visceral hypersensitivity. Lipid peroxidase and oxidative stress were indicated by increased plasma thiobarbituric acid reactive substances (TBARS) and diminished pancreatic manganese superoxide dismutase (MnSOD). The secondary sensitization associated with AHF-induced pancreatitis was effectively alleviated by the TRPV4 antagonist, HC 067047. Similarity of the results to those with the peripherally restricted μ-opiate receptor agonist, loperamide, suggested TRPV4 channel activated peripheral sensitization. This study using a reliable model that provides pre-clinical correlates of human chronic pancreatitis provides further evidence that TRPV4 channel is a potential therapeutic target for treatment of pancreatitis pain.

Keywords: HC 067047; TBARS; behavior; loperamide; rat; visceral pain.

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Conflict of interest statement

Conflict of interest statement

All authors declare no conflict of interest.

Figures

Fig. 1
Fig. 1. Pancreas Anatomy, Histology and Oxidative Indices
A. Control pancreas. The normal pancreas is a large diffuse glandular organ surrounded by duodenum, stomach and spleen. Gross divisions include the head (duodenal), body (biliary), and tail (gastro-splenic). B. AHF induced pancreatitis. The pancreas of rats with AHF induced pancreatitis is smaller and more translucent, indicative of tissue loss. A large portion of the gland is replaced by fat (black arrows). C. Sirius red fibrosis staining. Sirius red staining of control pancreas tissue shows minimal fibrous collagen. D. Numerous fibrotic regions are localized with Sirius red staining in pancreatic tissue from rats with AHF induced pancreatitis. E. MnSOD immunostaining intensity in pancreas. MnSOD immunoreactivity is present in the pancreatic tissue of control rats fed standard rodent chow. F. Sparse MnSOD immunoreactivity is observed in the core of the pancreatic lobes in rats with AHF induced pancreatitis suggesting decreased mitochondrial anti-oxidative capacity. G. The bar graph shows quantitation of the pancreatic tissue staining intensity of the MnSOD immunoreactivity among groups (n=4/group; *** p<0.001, standard chow vs. injury core and periphery of pancreas in AHF fed rats; ### p< 0.001, pancreas core vs. periphery). H. Plasma TBARS The metabolic byproduct thiobarbituric acid reactive substances (TBARS) in blood plasma, an indicator of lipid peroxidation, is significantly increased in rats with AHF induced pancreatitis (** p<0.01, chow vs. AHF fed, t-test).
Fig. 2
Fig. 2. Pain Related Behavioral Assessments
A. Footpad mechanical hypersensitivity. The 50% paw withdrawal threshold (g) to mechanical stimulation (von Frey fiber test) was similar between rats fed standard chow and the AHF fed group at baseline. In the AHF group, the mechanical threshold was progressively decreased beginning in week 3 and reached maximum hypersensitivity in week 5. The paw mechanical allodynia was maintained through the entire experimental time course (**** p<0.0001, two-way ANOVA, Bonferroni post-test). B. Abdominal heat hypersensitivity. The abdominal withdrawal latency (ABWL) was similar for standard chow control and AHF fed groups at baseline through week 1. Secondary heat hyperalgesia developed on the abdominal skin by the second week on the AHF diet. The abdominal withdrawal latency (ABWL) of the AHF induced pancreatitis group decreased from a baseline of 13.70 ± 1.1 s to 6.58 ± 0.32 s. This hypersensitivity level was maintained throughout the remainder of the experiment. This difference was statistically significant compared to the control chow fed group (****p<0.0001, two-way ANOVA, Bonferroni post-test).
Fig. 3
Fig. 3. Nocifensive Responses to Noxious 44°C Hotplate Stimulus in Week 6
A. Increased rearing events (10 min) in rats with AHF induced pancreatitis occurred on the 38°C and B. the 44°C hotplate. C. The first response hindpaw licking latency to the 44°C heat was significantly shorter in rats with AHF induced pancreatitis. D. The total number of hindpaw licking/guarding events per 10 min was dramatically increased in rats with AHF pancreatitis (* p<0.05, two-tailed t-test).
Fig. 4
Fig. 4. The Light/Dark Box Preference Test
The baseline from each parameter shows the averaged baseline behaviors for all animals before group assignment. A. Rats with AHF induced pancreatitis had a shortened latency to 1st crossing to the light side of the box. B. Rats with AHF induced pancreatitis spent a considerably longer time in the light compartment than did rats fed with standard chow or at baseline. C. The number of transitions between the light and dark compartments was increased in rats with AHF pancreatitis compared to controls fed standard chow or at baseline. D. Rats with AHF pancreatitis had a great number of rearing events compared to the normal chow controls and at baseline.
Fig. 5
Fig. 5. Effect of Peripherally Restricted Opiate, Loperamide
A. Paw mechanical allodynia. Rats fed with AHF for 6 weeks, were given loperamide (1mg/kg, i.p). Loperamide effectively attenuated the paw mechanical allodynia in rats with AHF pancreatitis. The effect began at 0.5 hour, peaked at 1 hour, and persisted for 4 hours. This effect was reversed by naloxone methiodide (n=6/group; **p<0.01; *** p<0.001, two-way ANOVA, Bonferroni post-test). B. Abdominal heat hyperalgesia. Rats with AHF pancreatitis were given loperamide (1mg/kg, i.p). Treatment effectively attenuated abdominal heat hyperalgesia. The effect began at 0.5hour, peaked at 1 hour, and persisted for 4hours. This effect was reversed by naloxone methiodide (n=6/group; *p<0.05; ** p<0.01; *** p<0.001; two-way ANOVA, Bonferroni post-test). C. Noxious 44°C hotplate stimulus: Loperamide treatment reduced the number of rearing events of rats with AHF pancreatitis on the 44°C hotplate and prolonged the first response latency. There was a statistically significant difference comparing AHF pancreatitis rats with/without drug treatment (n=6/group; *p< 0.05 by two-way ANOVA).
Fig. 6
Fig. 6. TRPV4 Antagonist HC067047
A. Dose response curves of TRPV4 antagonist HC067047 on rat hindpaw hypersensitivity HC067047 effectively alleviated mechanical hypersensitivity of rats with AHF pancreatitis in a dose dependent manner beginning at 0.5 hour and persisting for 3 hours. The 5 and 10 mg/kg doses effectively elevated the paw withdrawal threshold. B. Dose response curve of HC067047 on rat abdominal heat hypersensitivity. HC067047 also effectively prolonged the abdominal withdrawal latency (ABWL) response of the rats with AHF pancreatitis to heat stimulus in a dose dependent manner beginning at 0.5 hour and persisting for 3 hours. Effective doses of HC067047 were 5 and 10 mg/kg. C. HC067047 reduced nocifensive responses of AHF pancreatitis rats to noxious 44°C hotplate. HC067047 (10 mg/kg) prolonged the latency to first response and reduced the number of total hindpaw licking/guarding events of rats with AHF pancreatitis on the 44°C hotplate. The event/time curve of the drug treatment group had a significant right-ward shift (*p<0.05, two-way ANOVA, Bonferroni post-test).
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References

    1. Alessandri-Haber N, Dina OA, Yeh JJ, Parada CA, Reichling DB, Levine JD. Transient receptor potential vanilloid 4 is essential in chemotherapy-induced neuropathic pain in the rat. The Journal of neuroscience : the official journal of the Society for Neuroscience. 2004;24:4444–4452. - PMC - PubMed
    1. Ammann RW, Akovbiantz A, Largiader F, Schueler G. Course and outcome of chronic pancreatitis. Longitudinal study of a mixed medical-surgical series of 245 patients. Gastroenterology. 1984;86:820–828. - PubMed
    1. Bartho L, Benko R, Patacchini R, Petho G, Holzer-Petsche U, Holzer P, Lazar Z, Undi S, Illenyi L, Antal A, Horvath OP. Effects of capsaicin on visceral smooth muscle: a valuable tool for sensory neurotransmitter identification. European journal of pharmacology. 2004;500:143–157. - PubMed
    1. Bhutani MS, Pasricha PJ. Neurolytic Approaches for the Treatment of Pain in Patients with Chronic Pancreatitis. Current treatment options in gastroenterology. 2003;6:375–379. - PubMed
    1. Bilkei-Gorzo A, Gyertyan I, Levay G. mCPP-induced anxiety in the light-dark box in rats--a new method for screening anxiolytic activity. Psychopharmacology. 1998;136:291–298. - PubMed

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