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Modulation of inflammatory mediators in the trigeminal ganglion by botulinum neurotoxin type A: an organ culture study.

Edvinsson J, Warfvinge K, Edvinsson L - J Headache Pain (2015)

Bottom Line: Co-incubation with U0126 or BoNT-A retained the increased expression of SNAP-25, while it decreased the IL-1β immunoreactivity in neurons.It is clinically well recognized that treatment with corticosteroids will reduce the symptoms of chronic migraine; however this remedy is associated with long-term side effects.The results of the present work illustrate one way by which BoNT-A may modify these expressional alterations.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Lund University, Lund, Sweden, jacob.edvinsson@hotmail.com.

ABSTRACT

Background: Onabotulinumtoxin type A (BoNT-A) has been found to reduce pain in chronic migraine. The aim of the present study was to ask if BoNT-A can interact directly on sensory mechanisms in the trigeminal ganglion (TG) using an organ culture method.

Methods: To induce inflammation, rat TGs were incubated for 24 hrs with either the mitogen MEK1/2 inhibitor U0126, BoNT-A or NaCl. After this the TGs were prepared for immunohistochemistry. Sections of the TG were then incubated with primary antibodies against CGRP (neuronal transmitter), iNOS (inflammatory marker), IL-1β (Interleukin 1β), SNAP-25 (synaptic vesicle docking protein) or SV2-A (Botulinum toxin receptor element).

Results: We report that CGRP, iNOS, IL-1β, SNAP-25 and SV2-A were observed in fresh TG with a differential distribution. Interestingly, NaCl organ culture of the TG resulted in enhanced expression of CGRP and SNAP-25 in neurons and iNOS in SGCs. Co-incubation with U0126 or BoNT-A retained the increased expression of SNAP-25, while it decreased the IL-1β immunoreactivity in neurons. The iNOS expression in SGCs returned to levels observed in fresh specimens. Moreover, we observed no alteration SV2-A expression in SGCs. Thus, the overall picture is that both U0126 and BoNT-A have the ability to modify the expression of certain molecules in the TG.

Conclusion: We hypothesize that chronic migraine might be associated with some degree of inflammation in the TG that could involve both neurons and SGCs. It is clinically well recognized that treatment with corticosteroids will reduce the symptoms of chronic migraine; however this remedy is associated with long-term side effects. Understanding the mechanisms involved in the expressional alterations may suggest novel ways to modify the changes and indicate novel therapeutics. The results of the present work illustrate one way by which BoNT-A may modify these expressional alterations.

No MeSH data available.


Related in: MedlinePlus

CGRP immunohistochemistry. a Fresh TG contained both CGRP positive and negative neurons. The immunoreactivity was confined to the cytoplasm in a granular pattern, resembling staining of the endoplasmatic reticulum, and in some of the fibers. In TG incubated in medium containing saline, the number of neurons immunoreactive to CGRP seemed to be increased. The immunoreactivity was often spread in a granular matter in the entire cytoplasm as observed in the fresh TG. In the specimens incubated with U0126 or BoNT-A, the number of positive neurons increased and the immunoreactivity was found in the entire cytoplasm in almost all neurons. b To illustrate the microscopical findings, fluorescence intensity measurements were performed. The results confirm these findings; a tendency of intensity increase after 24 hrs of incubation with NaCl, U0126 or BoNT-A. Negative column is the same as in SNAP-25 diagram since the same secondary antibody is used in both experiments. Bars indicate SD
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Fig2: CGRP immunohistochemistry. a Fresh TG contained both CGRP positive and negative neurons. The immunoreactivity was confined to the cytoplasm in a granular pattern, resembling staining of the endoplasmatic reticulum, and in some of the fibers. In TG incubated in medium containing saline, the number of neurons immunoreactive to CGRP seemed to be increased. The immunoreactivity was often spread in a granular matter in the entire cytoplasm as observed in the fresh TG. In the specimens incubated with U0126 or BoNT-A, the number of positive neurons increased and the immunoreactivity was found in the entire cytoplasm in almost all neurons. b To illustrate the microscopical findings, fluorescence intensity measurements were performed. The results confirm these findings; a tendency of intensity increase after 24 hrs of incubation with NaCl, U0126 or BoNT-A. Negative column is the same as in SNAP-25 diagram since the same secondary antibody is used in both experiments. Bars indicate SD

Mentions: In the fresh TG, we observed both CGRP positive and negative neurons (Fig. 2a). The CGRP immunoreactivity was confined to the cytoplasm in a granular pattern, resembling staining of the endoplasmatic reticulum. In addition, some of the nerve fibers seen in TG were CGRP positive.Fig. 2


Modulation of inflammatory mediators in the trigeminal ganglion by botulinum neurotoxin type A: an organ culture study.

Edvinsson J, Warfvinge K, Edvinsson L - J Headache Pain (2015)

CGRP immunohistochemistry. a Fresh TG contained both CGRP positive and negative neurons. The immunoreactivity was confined to the cytoplasm in a granular pattern, resembling staining of the endoplasmatic reticulum, and in some of the fibers. In TG incubated in medium containing saline, the number of neurons immunoreactive to CGRP seemed to be increased. The immunoreactivity was often spread in a granular matter in the entire cytoplasm as observed in the fresh TG. In the specimens incubated with U0126 or BoNT-A, the number of positive neurons increased and the immunoreactivity was found in the entire cytoplasm in almost all neurons. b To illustrate the microscopical findings, fluorescence intensity measurements were performed. The results confirm these findings; a tendency of intensity increase after 24 hrs of incubation with NaCl, U0126 or BoNT-A. Negative column is the same as in SNAP-25 diagram since the same secondary antibody is used in both experiments. Bars indicate SD
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526514&req=5

Fig2: CGRP immunohistochemistry. a Fresh TG contained both CGRP positive and negative neurons. The immunoreactivity was confined to the cytoplasm in a granular pattern, resembling staining of the endoplasmatic reticulum, and in some of the fibers. In TG incubated in medium containing saline, the number of neurons immunoreactive to CGRP seemed to be increased. The immunoreactivity was often spread in a granular matter in the entire cytoplasm as observed in the fresh TG. In the specimens incubated with U0126 or BoNT-A, the number of positive neurons increased and the immunoreactivity was found in the entire cytoplasm in almost all neurons. b To illustrate the microscopical findings, fluorescence intensity measurements were performed. The results confirm these findings; a tendency of intensity increase after 24 hrs of incubation with NaCl, U0126 or BoNT-A. Negative column is the same as in SNAP-25 diagram since the same secondary antibody is used in both experiments. Bars indicate SD
Mentions: In the fresh TG, we observed both CGRP positive and negative neurons (Fig. 2a). The CGRP immunoreactivity was confined to the cytoplasm in a granular pattern, resembling staining of the endoplasmatic reticulum. In addition, some of the nerve fibers seen in TG were CGRP positive.Fig. 2

Bottom Line: Co-incubation with U0126 or BoNT-A retained the increased expression of SNAP-25, while it decreased the IL-1β immunoreactivity in neurons.It is clinically well recognized that treatment with corticosteroids will reduce the symptoms of chronic migraine; however this remedy is associated with long-term side effects.The results of the present work illustrate one way by which BoNT-A may modify these expressional alterations.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Lund University, Lund, Sweden, jacob.edvinsson@hotmail.com.

ABSTRACT

Background: Onabotulinumtoxin type A (BoNT-A) has been found to reduce pain in chronic migraine. The aim of the present study was to ask if BoNT-A can interact directly on sensory mechanisms in the trigeminal ganglion (TG) using an organ culture method.

Methods: To induce inflammation, rat TGs were incubated for 24 hrs with either the mitogen MEK1/2 inhibitor U0126, BoNT-A or NaCl. After this the TGs were prepared for immunohistochemistry. Sections of the TG were then incubated with primary antibodies against CGRP (neuronal transmitter), iNOS (inflammatory marker), IL-1β (Interleukin 1β), SNAP-25 (synaptic vesicle docking protein) or SV2-A (Botulinum toxin receptor element).

Results: We report that CGRP, iNOS, IL-1β, SNAP-25 and SV2-A were observed in fresh TG with a differential distribution. Interestingly, NaCl organ culture of the TG resulted in enhanced expression of CGRP and SNAP-25 in neurons and iNOS in SGCs. Co-incubation with U0126 or BoNT-A retained the increased expression of SNAP-25, while it decreased the IL-1β immunoreactivity in neurons. The iNOS expression in SGCs returned to levels observed in fresh specimens. Moreover, we observed no alteration SV2-A expression in SGCs. Thus, the overall picture is that both U0126 and BoNT-A have the ability to modify the expression of certain molecules in the TG.

Conclusion: We hypothesize that chronic migraine might be associated with some degree of inflammation in the TG that could involve both neurons and SGCs. It is clinically well recognized that treatment with corticosteroids will reduce the symptoms of chronic migraine; however this remedy is associated with long-term side effects. Understanding the mechanisms involved in the expressional alterations may suggest novel ways to modify the changes and indicate novel therapeutics. The results of the present work illustrate one way by which BoNT-A may modify these expressional alterations.

No MeSH data available.


Related in: MedlinePlus