Anti-neuropathic effects of Rosmarinus officinalis L. terpenoid fraction: relevance of nicotinic receptors

Abstract

Traditional uses and current results highlight the neuroprotective properties of Rosmarinus officinalis L. The compelling need for novel strategies able to relieve neuropathic pain encouraged us to analyze different rosemary leaf extracts in rats following chronic constriction injury (CCI) of sciatic nerve. Ethanol, acetone, and the innovative ultrasound-hexane extractive methods were used to obtain: EE, AE, and for hexane extracts UREprel and URE. Extracts were characterized in terms of typical constituents and repeatedly administered to CCI-rats (13-days treatment, from the day of surgery). URE showed the best efficacy and potency in reducing hypersensitivity to noxious- and non-noxious stimuli and spontaneous pain. URE contained the higher quantity of the terpenoid carnosic acid (CA) and its efficacy was compared to pure CA. Histological analysis of the sciatic nerve revealed that URE prevented axon and myelin derangement, edema and inflammatory infiltrate. In the dorsal horn of the spinal cord, URE did not reduce astrocyte activation. Both the pain reliever and the neuroconservative effects of URE were significantly prevented by the nicotinic receptor (nAChR) antagonist mecamylamine. In conclusion, the hexane-ultrasound rosemary extract is able to reduce neuropathic hypersensitivity and protect nervous tissues. Effectiveness is mainly related to the terpenoid fraction by mechanisms involving nAChRs.

Two-Chambered Chitosan Nerve Guides With Increased Bendability Support Recovery of Skilled Forelimb Reaching Similar to Autologous Nerve Grafts in the Rat 10 mm Median Nerve Injury and Repair Model

“…As such the model has distinct differences to other peripheral nerve injury models, e.g., loose ligation models of the rat sciatic nerve. Nerve ligation models are studied in the context of the development of neuropathic pain in which early events at the lesion sites are characterized by edema and inflammatory infiltration (e.g., Pacini et al, 2010; Di Cesare Mannelli et al, 2016). One leading event after nerve transection injury, besides axonal and myelin breakdown, is also recruitment of macrophages that help in myelin clearance during Wallerian degeneration over 3–6 weeks after the injury (Gaudet et al, 2011; Faroni et al, 2015; Jessen and Mirsky, 2016).…”

“…This was, however, never detected in other studies evaluating chitosan-based nerve guides before (e.g., Haastert-Talini et al, 2013; Stößel et al, 2018a,b). We further did not study effects of any complementary treatment to protect peripheral nerve arrangement and to prevent development of neuropathic pain, like, e.g., daily oral administration of rosemary extracts (Pacini et al, 2010; Di Cesare Mannelli et al, 2016), because the rat median nerve transection and repair model has not been reported before to induce neuropathic pain.…”

Effect of NIR laser therapy by MLS-MiS source against neuropathic pain in rats: in vivo and ex vivo analysis

“…On day 22, after the behavioural measurements, animals were sacrificed and the ipsilateral sciatic nerves were explanted. As previously reported, the portion containing the ligature was eliminated and a distance of 900 μm proximal to the ligation was chosen as optimal for evaluating the effect of laser treatment 9 . Contralateral nerves were also dissected, and equivalent portions were collected.…”

Efficacy of Posidonia oceanica Extract against Inflammatory Pain: In Vivo Studies in Mice

“…Voluntary movements associated with locomotion were not taken as a withdrawal response. Stimuli were applied on each anterior paw with an interval of 5 s. The measure was repeated 5 times, and the final value was obtained by averaging the 5 measures [35,36].…”