CONTROLLING THE ACTIVATION OF THE PROKINETICIN SYSTEM REDUCES NEUROINFLAMMATION AND ABOLISHES PAIN HYPERSENSITIVITY IN EXPERIMENTAL NEUROPATHIC PAIN
Tesi di Dottorato
Data di Pubblicazione:
2014
Citazione:
CONTROLLING THE ACTIVATION OF THE PROKINETICIN SYSTEM REDUCES NEUROINFLAMMATION AND ABOLISHES PAIN HYPERSENSITIVITY IN EXPERIMENTAL NEUROPATHIC PAIN / M. Castelli ; tutor: A. E. Panerai ; direttore della Scuola: A. E. Panerai. Università degli Studi di Milano, 2014 Dec 15. 27. ciclo, Anno Accademico 2014. [10.13130/m-castelli_phd2014-12-15].
Abstract:
Neuropathic pain is a chronic and debilitating disease that occurs secondarily to injury of the peripheral and/or central nervous system. This pathology affects million people in the world and can be classified as an incurable disease for the lack of valid treatments.
Neuronal injuries often arise from a nerve trauma or metabolic disease, such as diabetes, and neuropathic patients, whatever the cause, typically exhibit a mixture of sensory loss with ongoing spontaneous pain and enhanced sensitivity either to innocuous or painful stimuli. Although the underlying mechanisms are far to being elucidated, it is well established that neuronal injury not only results in profound modifications in the activity of sensory neurons and their central projection pathways, but is also coupled to a sustained immune response at different anatomical locations associated to chronic pain processing with an important contribution of cytokines and chemokines (Calvo et al., 2012; Sacerdote et al., 2013).
Since intensive researches over the past years have identified the prokineticins (PKs) as possible candidates for mediating these pathological neuro-immune interactions in pain, in these years of PhD school my research was focused on the characterization of the PKs system in the development of experimental neuropathic pain.
PKs family comprehends small chemokines-like proteins highly conserved across the species including the mammalian prokineticin 1 (PK1) and prokineticin 2 (PK2). These proteins modulate a large spectrum of biological activities in the organism. In particular it is well documented the pro-nociceptive/proinflammatory activity of the ligand PK2 (Negri et al., 2007). Two G protein-coupled receptors (PKR1 and PKR2) mediate PK2 actions.
PK2, binding to PKR1 and PKR2 widely distributed in the central nervous system, DRG, sensory neurons and in cells participating to immune and inflammatory responses, exerts in fact a critical role in pain perception inducing nociceptor sensitization and increasing the release of neuromediators implicated in pain processing such as CGRP and SP (Negri et al., 2007; DeFelice et al., 2012; Vellani et al., 2006). Moreover the ligand influences macrophages and T lymphocytes activity inducing a pro-inflammatory phenotype in the macrophage and skewing the Th1/Th2 balance towards a Th1 response (Martucci et al., 2006; Franchi et al., 2008).
In order to understand if PK2, PKR1 and PKR2 activities were necessary for the onset, maintenance and resolution of neuropathic pain, in this study, in vivo and ex-vivo experiments were performed using a non-peptidic PKR antagonist, named PC1, proved capable of antagonizing all pro-nociceptive effects induced by PK2 (Balboni et al., 2008; Giannini et al., 2009; Negri and Lattanzi, 2012).
The efficacy of PC1 treatment was evaluated in two different mouse models of painful neuropathy: a mononeuropathy induced by the chronic constriction injury (CCI) of sciatic nerve and a diabetic polyneuropathy induced by the injection of a pancreatic β cell toxin, streptozotocin (STZ).
CCI procedure was performed through three loose ligatures around the right common sciatic nerve while the diabetic painful neuropathy was induced in animals by the administration of either a single high dose (200 mg/kg) or repeated multi-lower doses (80 mg/kg) of STZ. Changes in pain behavior were evaluated measuring the paw withdrawal thresholds after noxious (hyperalgesia) and/or innocuous (allodynia) stimulation with the Plantar Test Apparatus and the Dynamic Plantar Aesthesiometer, respectively.
To check the efficacy of PC1 to counteract painful manifestations, 3 days after CCI surgery and 21 days after STZ administrations, time points corresponding to full neuropathic pain development, CCI-oper
Tipologia IRIS:
Tesi di dottorato
Keywords:
PKs system; neuropathic pain; cytokines
Elenco autori:
M. Castelli
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