The Antinociceptive, Antioxidant and Anti-Inflammatory Effects of 5-Fluoro-2-Oxindole during Inflammatory Pain.

Recent studies demonstrate that 5-fluoro-2-oxindole inhibits neuropathic pain but the antinociceptive actions of this drug and its effects on the plasticity, oxidative and inflammatory changes induced by peripheral inflammation as well as on the effects and expression of µ-opioid receptors (MOR) have not been evaluated. In C57BL/6 male mice with inflammatory pain provoked by the subplantar administration of complete Freund's adjuvant (CFA), we evaluated: (1) the antinociceptive actions of 5-fluoro-2-oxindole and its reversion with the HO-1 inhibitor, tin protoporphyrin IX (SnPP); (2) the effects of 5-fluoro-2-oxindole in the protein levels of mitogen-activated protein kinase (MAPK), Nrf2, NADPH quinone oxidoreductase1 (NQO1), heme oxygenase 1 (HO-1), oxidative stress marker (4-hydroxy-2-nonenal; 4-HNE), inducible nitric oxide synthase (NOS2), microglial markers (CD11b/c and IBA-1), and MOR in the spinal cord and/or paw of animals with inflammatory pain; (3) the antinociceptive effects of morphine in 5-fluoro-2-oxindole pre-treated animals. Treatment with 5 and 10 mg/kg of 5-fluoro-2-oxindole inhibited the allodynia and hyperalgesia induced by CFA in a different, time-dependent manner.

Treatment with 5-fluoro-2-oxindole Increases the Antinociceptive Effects of Morphine and Inhibits Neuropathic Pain.

The efficacy of µ-opioid receptors (MOR) in neuropathic pain is low and with numerous side effects that limited their use. Chronic neuropathic pain is also linked with emotional disorders that aggravate the sensation of pain and which treatment has not been resolved. This study investigates whether the administration of an oxindole, 5-fluoro-2-oxindole, could inhibit the nociceptive and emotional behaviors and increase the effectiveness of morphine via modulating the microglia and activating the nuclear factor erythroid-2 related factor 2 (Nrf2) signaling pathway and MOR expression.

Sulforaphane Inhibited the Nociceptive Responses, Anxiety- and Depressive-Like Behaviors Associated With Neuropathic Pain and Improved the Anti-allodynic Effects of Morphine in Mice.

Chronic neuropathic pain is associated with anxiety- and depressive-like disorders. Its treatment remains a serious clinical problem due to the lack of efficacy of the available therapeutic modalities. We investigated if the activation of the transcription factor Nrf2 could modulate the nociceptive and emotional disorders associated with persistent neuropathic pain and potentiated the analgesic activity of morphine.

Mechanism implicated in the anti-allodynic and anti-hyperalgesic effects induced by the activation of heme oxygenase 1/carbon monoxide signaling pathway in the central nervous system of mice with neuropathic pain.

The administration of a carbon monoxide-releasing compound (tricarbonyldichlororuthenium(II)dimer, CORM-2) or an heme oxygenase 1 (HO-1) inductor (cobalt protoporphyrin IX, CoPP) exerts potent antinociceptive effects during chronic pain, but their actions in the central nervous system of animals with neuropathic pain have not been evaluated. Our objective is to investigate the effects of these treatments on the oxidative, inflammatory and molecular changes induced by sciatic nerve injury in several brain areas. In male C57BL6 mice with neuropathic pain induced by the chronic constriction of sciatic nerve (CCI), we evaluated the effects of CORM-2 and CoPP on the expression of the nuclear factor erythroid 2-related factor 2 (Nrf2), HO-1 and NAD(P)H:quinone oxidoreductase-1 (NQO1), the microglial marker (CD11b/c), and the mitogen-activated protein kinases (MAPK) (JNK, ERK½ and P38) in the amygdala, prefrontal cortex, hippocampus, hypothalamus and spinal cord, by using western blot assay.

Treatment with Sulforaphane Produces Antinociception and Improves Morphine Effects during Inflammatory Pain in Mice.

The activation of nuclear factor erythroid 2-related factor 2 (Nrf2) exerts potent antioxidative and anti-inflammatory effects; however, its participation in the modulation of chronic inflammatory pain and on the antinociceptive effects of -opioid receptor (MOR) agonists has not been evaluated. We investigated whether the induction of Nrf2 could alleviate chronic inflammatory pain and augment the analgesic effects of morphine and mechanisms implicated. In male C57BL/6 mice with inflammatory pain induced by complete Freund's adjuvant (CFA) subplantarly administered, we assessed: 1) antinociceptive actions of the administration of 5 and 10 mg/kg of a Nrf2 activator, sulforaphane (SFN); and 2) effects of SFN on the antinociceptive actions of morphine and on protein levels of Nrf2, heme oxygenase 1 (HO-1), and NAD(P)H: quinone oxidoreductase 1 (NQO1) enzymes, microglial activation and inducible nitric oxide synthase (NOS2) overexpression, as well as on mitogen-activated protein kinase (MAPK) and MOR expression in the spinal cord and paw of animals with inflammatory pain.