Analgesic Effect of Grape Seed Proanthocyanidin Extract in Fibromyalgia Animal Model

Abstract

The acidic saline animal model of pain has been suggested to mimic fibromyalgia (FM). Oligomeric proanthocyanidin complexes (OPC) from grape seeds are known to act as an antioxidant. We studied the effects of OPC on the pain threshold in the acidic saline animal model of pain. The left gastrocnemius muscle was injected with 100 μl of saline at pH 4.0 under brief isoflurane anesthesia on days 0 and 5. Control rats (n=5) received identical injections of physiological saline (pH 7.2) on the same schedule. Rats (n=10) with acidic saline injection were separated into two study subgroups. After measurement of pre-drug pain thresholds, rats were injected intraperitoneally with either saline or OPC 300 mg/kg. Paw withdrawal thresholds to pressure were again measured 60 min after intraperitoneal injection. Nociceptive thresholds were measured with a Dynamic Plantar Aesthesiometer by applying an increasing pressure to right or left hind paw until the rat withdrew the paw. Compared to baseline (day 0), acid injections produced mechanical hyper-responsiveness on day 7 (pre-drug) in these rats [p<0.05]. A potent antihyperalgesic effect was observed when rats were injected intraperitoneally with OPC 300 mg/kg [injected paw, p=0.001; contralateral paw, p=0.002]. OPC treatment decreased the expression of acid sensing ion channel 3 in the brain motor cortex area on immunohistochemical staining when OPC 300 mg/kg was administered intraperitoneally in the animal model of FM pain [p<0.05]. Further research is required to determine the efficacy of OPC treatments in FM pain in humans.

Bioactive Compounds for Fibromyalgia-like Symptoms: A Narrative Review and Future Perspectives

“…Curcumin has been used for centuries in Indian and Chinese medicine due to its ability to impact a diverse range of molecular targets. Many studies using mice and rats have demonstrated that this bioactive compound has anti-inflammatory and antioxidant potential by suppressing numerous cell-signaling pathways, including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), signal transducer and activator of transcription 3 (STAT3), nuclear factor-erythroid factor 2-related factor 2 (Nrf2), ROS, cyclooxygenase-2 (COX-2), superoxide leukocyte recruitment, and oxidative stress [ 48 ].…”

“…In terms of FM-like symptoms using animals, Mun et al reported oligomeric proanthocyanidin complex (OPC) administration had anti-hyperalgesic effects in an acidic saline animal model that mimics fibromyalgia, due to OPC’s antioxidant and anti-inflammatory properties [ 48 ]. In the same animal study, authors found a decreased ASIC3 expression, an ion sensing channel present in central and peripheral nervous systems, in the M1 and M2 brains of hyperalgesic animals [ 48 ].…”