A minocycline derivative reduces nerve injury-induced allodynia, LPS-induced prostaglandin E2 microglial production and signaling via toll-like receptors 2 and 4

Abstract

Many studies have shown that minocycline, an antibacterial tetracycline, suppresses experimental pain. While minocycline’s positive effects on pain resolution suggest that clinical use of such drugs may prove beneficial, minocycline’s antibiotic actions and divalent cation (Ca2+; Mg2+) chelating effects detract from its potential utility. Thus, we tested the antiallodynic effect induced by a non-antibacterial, non-chelating minocycline derivative in a model of neuropathic pain and performed an initial investigation of its anti-inflammatory effects in vitro. Intraperitoneal minocycline (100 mg/kg) and 12S-hydroxy-1,12-pyrazolinominocycline (PMIN; 23.75, 47.50 or 95.00 mg/kg) reduce the mechanical allodynia induced by chronic constriction injury of mouse sciatic nerve. PMIN reduces the LPS-induced production of PGE2 by primary microglial cell cultures. Human embryonic kidney cells were transfected to express human toll-like receptors 2 and 4, and the signaling via both receptors stimulated with PAM3CSK4 or LPS (respectively) was affected either by minocycline or PMIN. Importantly, these treatments did not affect the cell viability, as assessed by MTT test. Altogether, these results reinforce the evidence that the anti-inflammatory and experimental pain suppressive effects induced by tetracyclines are neither necessarily linked to antibacterial nor to Ca2+ chelating activities. This study supports the evaluation of the potential usefulness of PMIN in the management of neuropathic pain, as its lack of antibacterial and Ca2+ chelating activities might confer greater safety over conventional tetracyclines.

Toll-like Receptor 4 and comorbid pain in Interstitial Cystitis/Bladder Pain Syndrome: A Multidisciplinary Approach to the Study of Chronic Pelvic Pain research network study

“…PBMCs were separated by Ficoll-paque gradient centrifugation within 30 minutes of blood collection and cultured in RPMI 1640 medium containing 10% fetal bovine serum, 100 U/ml penicillin and 100 ug/ml streptomycin for 3 days with TLR agonists at 37°C in a humidified incubator with 5% CO2. TLR-2 and TLR-4 agonists were selected on the basis of the role of these receptors in chronic pain in animal models and our previous findings linking them to symptoms in IC/BPS (Bastos et al, 2013; Hutchinson et al, 2008; Schrepf et al, 2014;). For stimulation of TLR-4, 50 ng/ml of Lipopolysaccharide (LPS) was used; for TLR-2 stimulation, 0.04 ng/ml of Staphylococcus aureus Cowan I (SAC) was used.…”

Inflammation and inflammatory control in interstitial cystitis/bladder pain syndrome: Associations with painful symptoms

“…PBMCs were separated by Ficoll-paque gradient centrifugation within 30 minutes of blood collection and cultured in RPMI 1640 medium containing 10% fetal bovine serum, 100 U/ml penicillin and 100 ug/ml streptomycin for 3 days at 37°C in a humidified incubator with 5% CO 2 and TLR agonists. TLR-2 and 4 agonists were selected on the basis of the role of these receptors in chronic pain in animal models [2,14]. For stimulation of TLR-4, 50 ng/ml of Lipopolysaccharide (LPS) was used; For TLR-2 stimulation, 0.04 ng/ml of Staphylococcus aureus Cowan I (SAC) was used.…”

Recent advances in understanding neuropathic pain: glia, sex differences, and epigenetics

“…These sex-related differences are suggested to be spinal cord specific. Attenuation of neuropathy-induced hypersensitivity in female mice following systemic minocycline 46 or in both sexes after systemic p38 inhibitor 45 was attributed to actions on peripheral immune cells 45, 47 .…”