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Up-regulation of brain-derived neurotrophic factor in primary afferent pathway regulates colon-to-bladder cross-sensitization in rat.

Xia CM, Gulick MA, Yu SJ, Grider JR, Murthy KS, Kuemmerle JF, Akbarali HI, Qiao LY - J Neuroinflammation (2012)

Bottom Line: Colonic inflammation did not alter either the morphology of the urinary bladder or the expression level of TRPV1 in this viscus.However, colonic inflammation decreased the inter-micturition intervals and decreased the quantities of urine voided.Primary afferent-mediated BDNF up-regulation in the sensory neurons regulates, at least in part, the bladder activity during colonic inflammation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Virginia Commonwealth University School of Medicine, 1220 East Broad Street, PO Box 0551, MMRB 5038, VA 23219 Richmond, Virginia, USA.

ABSTRACT

Background: In humans, inflammation of either the urinary bladder or the distal colon often results in sensory cross-sensitization between these organs. Limited information is known about the mechanisms underlying this clinical syndrome. Studies with animal models have demonstrated that activation of primary afferent pathways may have a role in mediating viscero-visceral cross-organ sensitization.

Methods: Colonic inflammation was induced by a single dose of tri-nitrobenzene sulfonic acid (TNBS) instilled intracolonically. The histology of the colon and the urinary bladder was examined by hematoxylin and eosin (H&E) stain. The protein expression of transient receptor potential (TRP) ion channel of the vanilloid type 1 (TRPV1) and brain-derived neurotrophic factor (BDNF) were examined by immunohistochemistry and/or western blot. The inter-micturition intervals and the quantity of urine voided were obtained from analysis of cystometrograms.

Results: At 3 days post TNBS treatment, the protein level of TRPV1 was increased by 2-fold (p < 0.05) in the inflamed distal colon when examined with western blot. TRPV1 was mainly expressed in the axonal terminals in submucosal area of the distal colon, and was co-localized with the neural marker PGP9.5. In sensory neurons in the dorsal root ganglia (DRG), BDNF expression was augmented by colonic inflammation examined in the L1 DRG, and was expressed in TRPV1 positive neurons. The elevated level of BDNF in L1 DRG by colonic inflammation was blunted by prolonged pre-treatment of the animals with the neurotoxin resiniferatoxin (RTX). Colonic inflammation did not alter either the morphology of the urinary bladder or the expression level of TRPV1 in this viscus. However, colonic inflammation decreased the inter-micturition intervals and decreased the quantities of urine voided. The increased bladder activity by colonic inflammation was attenuated by prolonged intraluminal treatment with RTX or treatment with intrathecal BDNF neutralizing antibody.

Conclusion: Acute colonic inflammation increases bladder activity without affecting bladder morphology. Primary afferent-mediated BDNF up-regulation in the sensory neurons regulates, at least in part, the bladder activity during colonic inflammation.

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Histologic changes and TRPV1 immunoreactivity in the distal colon and the urinary bladder during colonic inflammation. TNBS treatment resulted in inflammatory response of the distal colon (A-B) and increased immunoreactivity of TRPV1 in the distal colon (E-F). Colonic inflammation was not accompanied by bladder inflammation (C-D), or changes in the TRPV1 immunoreactivity in the urinary bladder (G-H). Four independent experiments showed consistent results. Quantification of the results were shown in I and J. Bar = 300 μm in A-D; Bar = 50 μm in E-H. *, p < 0.05.
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Figure 1: Histologic changes and TRPV1 immunoreactivity in the distal colon and the urinary bladder during colonic inflammation. TNBS treatment resulted in inflammatory response of the distal colon (A-B) and increased immunoreactivity of TRPV1 in the distal colon (E-F). Colonic inflammation was not accompanied by bladder inflammation (C-D), or changes in the TRPV1 immunoreactivity in the urinary bladder (G-H). Four independent experiments showed consistent results. Quantification of the results were shown in I and J. Bar = 300 μm in A-D; Bar = 50 μm in E-H. *, p < 0.05.

Mentions: We compared the histology of the distal colon and the urinary bladder before and after induction of colonic inflammation. H&E staining (Figure 1A-D) showed that the distal colon had the appearance of severe inflammatory infiltration, edema, loss of the mucosal architecture, high level of vascular density, and increases in the thickness of muscular wall and the width of the submucosal spaces (compare Figure 1B to 1A). The histology of the urinary bladder appeared normal in terms of the structure and folds of the urothelium, the size of the gap of the suburothelium space, and the thickness of the muscular wall (compare Figure 1D to 1C; Figure 1I shows the relative damage scores of the colon and the urinary bladder). To characterize the sensory profile in the distal colon and the urinary bladder, we examined the expression of the sensory marker TRPV1 in these organs with immunohistochemistry and western blot techniques. During colonic inflammation, the TRPV1-like immunoreactivity was dramatically enhanced within the muscular layer (indicated by *) and the submucosal plexus (indicated by #) of the distal colon (Figure 1F) when compared to the non-inflamed distal colon (Figure 1E, J). The density of TRPV1 immunoreactivity was not altered in the urinary bladder before (Figure 1G) and after (Figure 1H) induction of colonic inflammation. To examine the specificity of the TRPV1-immunoreactive structures in the distal colon, we performed pre-absorption assay with a TRPV1 blocking peptide (5 μg/mL, Santa Cruz, CA) and found that this blocking peptide completely abolished the TRPV1-like immunoreactivity in both regions of the muscular layer and the submucosal area (compare Figure 2B to 2A), suggesting that the punctuated staining in the distal colon by this TRPV1 antibody was specific TRPV1 immunoreactivity. Further examination with double immunostaining showed that the TRPV1 immunoreactivity in the inflamed distal colon was expressed in PGP9.5 positive structures (Figure 2C-H). These co-localization studies were conducted with transverse sections (Figure 2C-E) and the whole-mount preparation of the inflamed distal colon (Figure 2F-H). Both methods demonstrated consistent results showing that all TRPV1 immunoreactivity was expressed in PGP9.5 positive structures (Figure 2C-H, white arrows), but not all PGP9.5 positive structures contained TRPV1 (Figure 2C-H, blue arrows).


Up-regulation of brain-derived neurotrophic factor in primary afferent pathway regulates colon-to-bladder cross-sensitization in rat.

Xia CM, Gulick MA, Yu SJ, Grider JR, Murthy KS, Kuemmerle JF, Akbarali HI, Qiao LY - J Neuroinflammation (2012)

Histologic changes and TRPV1 immunoreactivity in the distal colon and the urinary bladder during colonic inflammation. TNBS treatment resulted in inflammatory response of the distal colon (A-B) and increased immunoreactivity of TRPV1 in the distal colon (E-F). Colonic inflammation was not accompanied by bladder inflammation (C-D), or changes in the TRPV1 immunoreactivity in the urinary bladder (G-H). Four independent experiments showed consistent results. Quantification of the results were shown in I and J. Bar = 300 μm in A-D; Bar = 50 μm in E-H. *, p < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3298724&req=5

Figure 1: Histologic changes and TRPV1 immunoreactivity in the distal colon and the urinary bladder during colonic inflammation. TNBS treatment resulted in inflammatory response of the distal colon (A-B) and increased immunoreactivity of TRPV1 in the distal colon (E-F). Colonic inflammation was not accompanied by bladder inflammation (C-D), or changes in the TRPV1 immunoreactivity in the urinary bladder (G-H). Four independent experiments showed consistent results. Quantification of the results were shown in I and J. Bar = 300 μm in A-D; Bar = 50 μm in E-H. *, p < 0.05.
Mentions: We compared the histology of the distal colon and the urinary bladder before and after induction of colonic inflammation. H&E staining (Figure 1A-D) showed that the distal colon had the appearance of severe inflammatory infiltration, edema, loss of the mucosal architecture, high level of vascular density, and increases in the thickness of muscular wall and the width of the submucosal spaces (compare Figure 1B to 1A). The histology of the urinary bladder appeared normal in terms of the structure and folds of the urothelium, the size of the gap of the suburothelium space, and the thickness of the muscular wall (compare Figure 1D to 1C; Figure 1I shows the relative damage scores of the colon and the urinary bladder). To characterize the sensory profile in the distal colon and the urinary bladder, we examined the expression of the sensory marker TRPV1 in these organs with immunohistochemistry and western blot techniques. During colonic inflammation, the TRPV1-like immunoreactivity was dramatically enhanced within the muscular layer (indicated by *) and the submucosal plexus (indicated by #) of the distal colon (Figure 1F) when compared to the non-inflamed distal colon (Figure 1E, J). The density of TRPV1 immunoreactivity was not altered in the urinary bladder before (Figure 1G) and after (Figure 1H) induction of colonic inflammation. To examine the specificity of the TRPV1-immunoreactive structures in the distal colon, we performed pre-absorption assay with a TRPV1 blocking peptide (5 μg/mL, Santa Cruz, CA) and found that this blocking peptide completely abolished the TRPV1-like immunoreactivity in both regions of the muscular layer and the submucosal area (compare Figure 2B to 2A), suggesting that the punctuated staining in the distal colon by this TRPV1 antibody was specific TRPV1 immunoreactivity. Further examination with double immunostaining showed that the TRPV1 immunoreactivity in the inflamed distal colon was expressed in PGP9.5 positive structures (Figure 2C-H). These co-localization studies were conducted with transverse sections (Figure 2C-E) and the whole-mount preparation of the inflamed distal colon (Figure 2F-H). Both methods demonstrated consistent results showing that all TRPV1 immunoreactivity was expressed in PGP9.5 positive structures (Figure 2C-H, white arrows), but not all PGP9.5 positive structures contained TRPV1 (Figure 2C-H, blue arrows).

Bottom Line: Colonic inflammation did not alter either the morphology of the urinary bladder or the expression level of TRPV1 in this viscus.However, colonic inflammation decreased the inter-micturition intervals and decreased the quantities of urine voided.Primary afferent-mediated BDNF up-regulation in the sensory neurons regulates, at least in part, the bladder activity during colonic inflammation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Virginia Commonwealth University School of Medicine, 1220 East Broad Street, PO Box 0551, MMRB 5038, VA 23219 Richmond, Virginia, USA.

ABSTRACT

Background: In humans, inflammation of either the urinary bladder or the distal colon often results in sensory cross-sensitization between these organs. Limited information is known about the mechanisms underlying this clinical syndrome. Studies with animal models have demonstrated that activation of primary afferent pathways may have a role in mediating viscero-visceral cross-organ sensitization.

Methods: Colonic inflammation was induced by a single dose of tri-nitrobenzene sulfonic acid (TNBS) instilled intracolonically. The histology of the colon and the urinary bladder was examined by hematoxylin and eosin (H&E) stain. The protein expression of transient receptor potential (TRP) ion channel of the vanilloid type 1 (TRPV1) and brain-derived neurotrophic factor (BDNF) were examined by immunohistochemistry and/or western blot. The inter-micturition intervals and the quantity of urine voided were obtained from analysis of cystometrograms.

Results: At 3 days post TNBS treatment, the protein level of TRPV1 was increased by 2-fold (p < 0.05) in the inflamed distal colon when examined with western blot. TRPV1 was mainly expressed in the axonal terminals in submucosal area of the distal colon, and was co-localized with the neural marker PGP9.5. In sensory neurons in the dorsal root ganglia (DRG), BDNF expression was augmented by colonic inflammation examined in the L1 DRG, and was expressed in TRPV1 positive neurons. The elevated level of BDNF in L1 DRG by colonic inflammation was blunted by prolonged pre-treatment of the animals with the neurotoxin resiniferatoxin (RTX). Colonic inflammation did not alter either the morphology of the urinary bladder or the expression level of TRPV1 in this viscus. However, colonic inflammation decreased the inter-micturition intervals and decreased the quantities of urine voided. The increased bladder activity by colonic inflammation was attenuated by prolonged intraluminal treatment with RTX or treatment with intrathecal BDNF neutralizing antibody.

Conclusion: Acute colonic inflammation increases bladder activity without affecting bladder morphology. Primary afferent-mediated BDNF up-regulation in the sensory neurons regulates, at least in part, the bladder activity during colonic inflammation.

Show MeSH
Related in: MedlinePlus