Neuroadaptations in Estrogen Signaling in an Animal Model of Complex Regional Pain Syndrome & Alcoholic Neuropathy
Publication Date
July 2019
Location
LSU Health Medical Education Building
Document Type
Abstract
Start Date
26-7-2019 9:00 AM
End Date
26-7-2019 12:00 PM
Description
Complex Regional Pain Syndrome (CRPS) is a chronic pain condition that occurs following injury or immobilization to a limb and shares many symptoms with alcoholic neuropathy, including an increased sensitivity to painful stimuli (allodynia). Both CRPS and alcoholic neuropathy disproportionately affect women, leading us to hypothesize that estrogen and progesterone may play a role in the pathophysiology of these two conditions. Based on estrogen’s neuroprotective properties, we predicted hyperalgesia would correlate with reduced estrogen receptor phosphorylation and G protein-coupled estrogen receptor (GPER) levels in pain-associated brain areas. CRPS was modeled in female rats by using unilateral hind limb immobilization for seven days, allowing the other limb to serve as a within-subjects control. To model alcoholic neuropathy, half the rats were subjected to a ten-week Liber-DeCarli alcohol liquid diet prior to immobilization. To investigate the role of ovarian hormones, half of the animals underwent ovariectomy (OVX) and the other half a sham operation. Allodynia was quantified as mechanical paw withdrawal thresholds using the von Frey method The behavioral findings from this experiment showed that rats that had been subjected to cast immobilization (p=0.014) and a liquid alcohol diet (p=0.005) had lower paw withdrawal thresholds the days following cast removal, and these effects were seen both separately and additively. This demonstrated that chronic alcohol intake increased pain sensitivity in our model of CRPS. However, OVX did not interact with these effects. Through the use of Western blot analysis, several estrogen and progesterone receptors were targeted and their concentrations were analyzed to determine the relationship between the hormone levels and pain sensitivity. In this study, we have focused on the cingulate cortex, a main cortical area that brings pain into conscious awareness.
Recommended Citation
Urbina Lopez, Amy P., "Neuroadaptations in Estrogen Signaling in an Animal Model of Complex Regional Pain Syndrome & Alcoholic Neuropathy" (2019). Summer Research Internship Program. 34.
https://digitalscholar.lsuhsc.edu/srip/2019/undergrad/34
Neuroadaptations in Estrogen Signaling in an Animal Model of Complex Regional Pain Syndrome & Alcoholic Neuropathy
LSU Health Medical Education Building
Complex Regional Pain Syndrome (CRPS) is a chronic pain condition that occurs following injury or immobilization to a limb and shares many symptoms with alcoholic neuropathy, including an increased sensitivity to painful stimuli (allodynia). Both CRPS and alcoholic neuropathy disproportionately affect women, leading us to hypothesize that estrogen and progesterone may play a role in the pathophysiology of these two conditions. Based on estrogen’s neuroprotective properties, we predicted hyperalgesia would correlate with reduced estrogen receptor phosphorylation and G protein-coupled estrogen receptor (GPER) levels in pain-associated brain areas. CRPS was modeled in female rats by using unilateral hind limb immobilization for seven days, allowing the other limb to serve as a within-subjects control. To model alcoholic neuropathy, half the rats were subjected to a ten-week Liber-DeCarli alcohol liquid diet prior to immobilization. To investigate the role of ovarian hormones, half of the animals underwent ovariectomy (OVX) and the other half a sham operation. Allodynia was quantified as mechanical paw withdrawal thresholds using the von Frey method The behavioral findings from this experiment showed that rats that had been subjected to cast immobilization (p=0.014) and a liquid alcohol diet (p=0.005) had lower paw withdrawal thresholds the days following cast removal, and these effects were seen both separately and additively. This demonstrated that chronic alcohol intake increased pain sensitivity in our model of CRPS. However, OVX did not interact with these effects. Through the use of Western blot analysis, several estrogen and progesterone receptors were targeted and their concentrations were analyzed to determine the relationship between the hormone levels and pain sensitivity. In this study, we have focused on the cingulate cortex, a main cortical area that brings pain into conscious awareness.
Comments
Mentor: Dr. Scott Edwards, PhD