3-(2-hydroxy-4-(1-1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol and Anemia--Sickle-Cell

Pain is a hallmark feature of sickle cell disease (SCD). Subjects typically quantify pain by themselves, which can be biased by other factors leading to overtreatment or under-treatment. Reliable and accurate quantification of pain, in real time, might enable to provide appropriate levels of analgesic treatment. The mouse grimace scale (MGS), a standardized behavioral coding system with high accuracy and reliability has been used to quantify varied types of pain. We hypothesized that addition of the objective parameters of body length and back curvature will strengthen the reproducibility of MGS. We examined MGS scores and body length and back curvature of transgenic BERK sickle and control mice following cold treatment or following treatment with analgesic cannabinoid CP55,940. We observed that sickle mice demonstrated decreased length and increased back curvature in response to cold. These observations correlate with changes in facial expression for the MGS score. CP55,940 treatment of sickle mice showed an increase in body length and a decrease in back curvature concordant with MGS scores indicative of an analgesic effect. Thus, body parameters combined with facial expressions may provide a quantifiable unbiased method for objective measure of pain in SCD.

Topics: Analgesics; Anemia, Sickle Cell; Animals; Behavior, Animal; Cold Temperature; Cyclohexanols; Disease Models, Animal; Facial Expression; Female; Humans; Male; Mice; Mice, Transgenic; Pain; Pain Measurement; Posture; Reproducibility of Results; Research Design

The clinical management of severe pain associated with sickle cell disease (SCD) remains challenging. Development of an optimal therapy would be facilitated by use of murine model(s) with varying degrees of sickling and pain tests that are most sensitive to vaso-occlusion. We found that young (≤3 months old) NY1DD and S+S(Antilles) mice (having modest and moderate sickle phenotype, respectively) exhibited evidence of deep tissue/musculoskeletal pain. Deep tissue pain and cold sensitivity in S+S(Antilles) mice increased significantly with both age and incitement of hypoxia/reoxygenation (H/R). C57/BL6 mice (genetic background strain of NY1DD and S+S(Antilles) ) were hypersensitive to mechanical and heat stimuli, even without the sickle transgene. H/R treatment of HbSS-BERK mice with severe sickle phenotype resulted in significantly decreased withdrawal thresholds and enhanced mechanical, thermal and deep tissue hyperalgesia. Deep hyperalgesia incited by H/R in HbSS-BERK was ameliorated by CP 55940, a cannabinoid receptor agonist. Thus, assessment of deep tissue pain appears to be the most sensitive measure for studying pain mechanisms across mouse models of SCD, and HbSS-BERK mice may be the best model for vaso-occlusive and chronic pain of SCD.

Topics: Age Factors; Analgesics; Anemia, Sickle Cell; Animals; Cannabinoid Receptor Antagonists; Cyclohexanols; Disease Models, Animal; Humans; Hyperalgesia; Hypoxia; Mice; Mice, Inbred C57BL; Mice, Transgenic; Pain; Pain Measurement; Temperature

Sickle cell disease causes severe pain. We examined pain-related behaviors, correlative neurochemical changes, and analgesic effects of morphine and cannabinoids in transgenic mice expressing human sickle hemoglobin (HbS). Paw withdrawal threshold and withdrawal latency (to mechanical and thermal stimuli, respectively) and grip force were lower in homozygous and hemizygous Berkley mice (BERK and hBERK1, respectively) compared with control mice expressing human hemoglobin A (HbA-BERK), indicating deep/musculoskeletal and cutaneous hyperalgesia. Peripheral nerves and blood vessels were structurally altered in BERK and hBERK1 skin, with decreased expression of mu opioid receptor and increased calcitonin gene-related peptide and substance P immunoreactivity. Activators of neuropathic and inflammatory pain (p38 mitogen-activated protein kinase, STAT3, and mitogen-activated protein kinase/extracellular signal-regulated kinase) showed increased phosphorylation, with accompanying increase in COX-2, interleukin-6, and Toll-like receptor 4 in the spinal cord of hBERK1 compared with HbA-BERK. These neurochemical changes in the periphery and spinal cord may contribute to hyperalgesia in mice expressing HbS. In BERK and hBERK1, hyperalgesia was markedly attenuated by morphine and cannabinoid receptor agonist CP 55940. We show that mice expressing HbS exhibit characteristics of pain observed in sickle cell disease patients, and neurochemical changes suggestive of nociceptor and glial activation. Importantly, cannabinoids attenuate pain in mice expressing HbS.

Topics: Anemia, Sickle Cell; Animals; Behavior, Animal; Calcitonin Gene-Related Peptide; Cannabinoid Receptor Agonists; Cannabinoids; Cyclohexanols; Disease Models, Animal; Female; Hemoglobin, Sickle; Humans; Hyperalgesia; Male; Mice; Mice, Knockout; Mice, Transgenic; Morphine; Neuroglia; Pain; Receptors, Opioid, mu; Recombinant Proteins; Skin; Spinal Cord; Substance P