Zerumbone Ameliorates Neuropathic Pain Symptoms via Cannabinoid and PPAR Receptors Using In Vivo and In Silico Models

Abstract

Neuropathic pain is a chronic pain condition persisting past the presence of any noxious stimulus or inflammation. Zerumbone, of the Zingiber zerumbet ginger plant, has exhibited anti-allodynic and antihyperalgesic effects in a neuropathic pain animal model, amongst other pharmacological properties. This study was conducted to further elucidate the mechanisms underlying zerumbone's antineuropathic actions. Research on therapeutic agents involving cannabinoid (CB) and peroxisome proliferator-activated receptors (PPARs) is rising. These receptor systems have shown importance in causing a synergistic effect in suppressing nociceptive processing. Behavioural responses were assessed using the von Frey filament test (mechanical allodynia) and Hargreaves plantar test (thermal hyperalgesia), in chronic constriction injury (CCI) neuropathic pain mice. Antagonists SR141716 (CB₁ receptor), SR144528 (CB₂ receptor), GW6471 (PPARα receptor) and GW9662 (PPARγ receptor) were pre-administered before the zerumbone treatment. Our findings indicated the involvement of CB₁, PPARα and PPARγ in zerumbone's action against mechanical allodynia, whereas only CB₁ and PPARα were involved against thermal hyperalgesia. Molecular docking studies also suggest that zerumbone has a comparable and favourable binding affinity against the respective agonist on the CB and PPAR receptors studied. This finding will contribute to advance our knowledge on zerumbone and its significance in treating neuropathic pain.

Keywords: cannabinoid; chronic constriction injury; neuropathic pain; peroxisome proliferator-activated receptors (PPAR); zerumbone.

Figure 1

The effect of cannabinoid receptor antagonists’ co-administration with a vehicle on mechanical allodynia in CCI-induced neuropathic pain mice. Each column represents the mean ± SEM, n = 6 mice per group. ^#### p < 0.0001 as compared to the sham group and **** p < 0.0001 as compared to the vehicle group. Sham (SHM), Vehicle (VEH: 10 mL/kg, i.p.), Zerumbone (Z: 10 mg/kg, i.p.), Antagonists; SR141716, CB₁ (S141: 1 mg/kg, i.p.), SR144528, CB₂ (S144: 1 mg/kg, i.p.).

Figure 2

The effect of cannabinoid receptor antagonists’ co-administration with zerumbone on mechanical allodynia in CCI-induced neuropathic pain mice. Each column represents the mean ± SEM, n = 6 mice per group. ^#### p < 0.0001 as compared to the sham group, **** p < 0.0001 as compared to the vehicle group and ⁺⁺⁺⁺ p < 0.0001 as compared to the zerumbone-treated group. Sham (SHM), Vehicle (VEH: 10 mL/kg, i.p.), Zerumbone (Z: 10 mg/kg, i.p.), Antagonists; SR141716, CB₁ (S141: 1 mg/kg, i.p.), SR144528, CB₂ (S144: 1 mg/kg, i.p.).

Figure 3

The effect of cannabinoid receptor antagonists’ co-administration with a vehicle on thermal hyperalgesia CCI-induced neuropathic pain mice. Each column represents the mean ± SEM, n = 6 mice per group. ^#### p < 0.0001 as compared to the sham group and **** p < 0.0001 as compared to the vehicle group. Sham (SHM), Vehicle (VEH: 10 mL/kg, i.p.), Zerumbone (Z: 10 mg/kg, i.p.), Antagonists; SR141716, CB₁ (S141: 1 mg/kg, i.p.), SR144528, CB₂ (S144: 1 mg/kg, i.p.).

Figure 4

The effect of cannabinoid receptor antagonists’ co-administration with zerumbone on thermal hyperalgesia CCI-induced neuropathic pain mice. Each column represents the mean ± SEM, n = 6 mice per group. ^# p < 0.05, ^#### p < 0.0001 as compared to the sham group, **** p < 0.0001 as compared to the vehicle group and ⁺⁺⁺⁺ p < 0.0001 as compared to the zerumbone-treated group. Sham (SHM), Vehicle (VEH: 10 mL/kg, i.p.), Zerumbone (Z: 10 mg/kg, i.p.), Antagonists; SR141716, CB₁ (S141: 1 mg/kg, i.p.), SR144528, CB₂ (S144: 1 mg/kg, i.p.).

Figure 5

Predicted binding mode from the docking simulation of zerumbone with the active residues of CB₁ (left) and CB₂ (right) receptors.

Figure 6

The effect of PPAR antagonists’ co-administration with a vehicle on mechanical allodynia in CCI-induced neuropathic pain mice. Each column represents the mean ± SEM, n = 6 mice per group. ^#### p < 0.0001 as compared to the sham group and **** p < 0.0001 as compared to the vehicle group. Sham (SHM), Vehicle (VEH: 10 mL/kg, i.p.), Zerumbone (Z: 10 mg/kg, i.p.), Antagonists; GW6471, PPARα (G64: 1 mg/kg, i.p.), GW9662, PPARγ (G96: 1 mg/kg, i.p.).

Figure 7

The effect of PPAR antagonists’ co-administration with zerumbone on mechanical allodynia in CCI-induced neuropathic pain mice. Each column represents the mean ± SEM, n = 6 mice per group. ^#### p < 0.0001 as compared to the sham group, **** p < 0.0001 as compared to the vehicle group and ⁺⁺⁺⁺ p < 0.0001 as compared to the zerumbone-treated group. Sham (SHM), Vehicle (VEH: 10 mL/kg, i.p.), Zerumbone (Z: 10 mg/kg, i.p.), Antagonists; GW6471, PPARα (G64: 1 mg/kg, i.p.), GW9662, PPARγ (G96: 1 mg/kg, i.p.).

Figure 8

The effect of PPAR antagonists’ co-administration with vehicle thermal hyperalgesia in CCI-induced neuropathic pain mice. Each column represents the mean ± SEM, n = 6 mice per group, ^#### p < 0.0001 as compared to the sham group and **** p < 0.0001 as compared to the vehicle group. Sham (SHM), Vehicle (VEH: 10 mL/kg, i.p.), Zerumbone (Z: 10 mg/kg, i.p.), Antagonists; GW6471, PPARα (G64: 1 mg/kg, i.p.), GW9662, PPARγ (G96: 1 mg/kg, i.p.).

Figure 9

The effect of PPAR antagonists’ co-administration with zerumbone on thermal hyperalgesia in CCI-induced neuropathic pain mice. Each column represents the mean ± SEM, n = 6 mice per group. ^## p < 0.01, ^#### p < 0.0001 as compared to the sham group, **** p < 0.0001 as compared to the vehicle group and ⁺⁺⁺⁺ p < 0.0001 as compared to the zerumbone-treated group. Sham (SHM), Vehicle (VEH: 10 mL/kg, i.p.), Zerumbone (Z: 10 mg/kg, i.p.), Antagonists; GW6471, PPARα (G64: 1 mg/kg, i.p.), GW9662, PPARγ (G96: 1 mg/kg, i.p.).

Figure 10

Predicted binding mode from the docking simulation of zerumbone with the active residues of PPARα (left) and PPARγ (right) receptors.