The Effect of Nitric Oxide Inhibition in Spinal Cord Injured Humans with and without Preserved Sympathetic Control of the Vasculature

Nitric oxide synthases: A delicate dance between bone regeneration and neuronal birth

Spinal cord injury (SCI) is a devastating condition resulting from traumatic or nontraumatic injury/chronic disorder. The pathogenesis of SCI necessitates a comprehensive approach, as it involves therapeutic strategies addressing both bone (spine) and neural (spinal cord) damage. This review centers on the pivotal role of nitric oxide (NO) and its synthesizing enzymes, nitric oxide synthases (NOS), in mediating the crosstalk between osteogenesis and neurogenesis. NO's effects are context-dependent, exhibiting a delicate balance between beneficial and detrimental actions. Reduced levels of nitric oxide (NO), primarily derived from endothelial NOS (eNOS), tipically stimulate osteoblast activity and promote neurogenesis by influencing neural stem cell (NSC) migration and differentiation. Conversely, elevated NO levels, predominantly from inducible NOS (iNOS), tipically triggered by inflammation, inhibit both processes through pro-apoptotic mechanisms. Nevertheless, these phenomena are not merely simplistic; they can be influenced by a variety of other factors. We explore the intricate interplay of NO/NOS with key signaling pathways crucial in neurogenesis and osteogenesis, including mechanical stimuli, Wnt, interleukins, BMPs, NF-κB, etc., revealing their influence on neuroinflammation, neurogenesis, and osteoblast differentiation. The temporal and spatial dynamics of NO/NOS activity and the implications for therapeutic intervention have been discussed. Precise modulation of NO levels and NOS isoforms, potentially through targeted therapies manipulating these interacting signaling pathways, emerges as a promising strategy for promoting bone and neural regeneration. This review highlights the critical need for a balanced approach in therapeutic strategies to harness the beneficial effects of NO/NOS while mitigating its detrimental consequences.

N(Omega)-nitro-l-arginine methyl ester potentiates lidocaine analgesic and anaesthetic effect in rats

OBJECTIVES

The purpose of the experiment was to study the effect of L-NAME (N(Omega)-nitro-L-arginine methyl ester) and its cotreatment with lidocaine on the spinal block and infiltrative cutaneous analgesia.

METHODS

The quality of cutaneous analgesia was examined by the block of the cutaneous trunci muscle reflexes following needle stimuli in the rat. Spinal anaesthetic potency was assessed by measuring three neurobehavioral examinations of nociceptive, proprioceptive and motor function following intrathecal injection in the rat.

KEY FINDINGS

L-NAME (0.6, 6 and 60 nmol) when cotreatment with lidocaine (ED50) produced dose-related cutaneous analgesia. Coadministration of L-NAME (0.6 μmol) with lidocaine intensified (P < 0.01) and prolonged (P < 0.001) cutaneous analgesia, whereas subcutaneous L-NAME (0.6 μmol) and saline did not provoke cutaneous analgesic effects. Adding L-NAME (2.5 μmol) to lidocaine intrathecally prolonged spinal sensory and motor block (P < 0.01), while intrathecal L-NAME (2.5 μmol) or 5% dextrose (vehicle) produced no spinal block.

CONCLUSIONS

L-NAME at 60 nmol (the minimum effective dose) increases and prolongs the effect of cutaneous analgesia of lidocaine. L-NANE at an ineffective dose potentiates lidocaine analgesic and anaesthetic effects.

Administration of chlorogenic acid alleviates spinal cord injury via TLR4/NF‑κB and p38 signaling pathway anti‑inflammatory activity

Chlorogenic acid, as a secondary metabolite of plants, exhibits a variety of effects including free radical scavenging, antiseptic, anti‑inflammatory and anti‑viral, in addition to its ability to reduce blood glucose, protect the liver and act as an anti‑hyperlipidemic agent and cholagogue. The present study demonstrated that administration of chlorogenic acid alleviated spinal cord injury (SCI) via anti‑inflammatory activity mediated by nuclear factor (NF)‑κB and p38 signaling pathways. Wistar rats were used to structure a SCI model rat to explore the effects of administration of chlorogenic acid on SCI. The Basso, Beattie and Bresnahan test was executed for assessment of neuronal functional recovery and then spinal cord tissue wet/dry weight ratio was recorded. The present study demonstrated that chlorogenic acid increased SCI‑inhibition of BBB scores and decreased SCI‑induction of spinal cord wet/dry weight ratio in rats. In addition, chlorogenic acid suppressed SCI‑induced inflammatory activity, inducible nitric oxide synthase activity and cyclooxygenase‑2 protein expression in the SCI rat. Furthermore, chlorogenic acid suppressed Toll like receptor (TLR)‑4/myeloid differentiation primary response 88 (MyD88)/NF‑κB/IκB signaling pathways and downregulated p38 mitogen activated protein kinase protein expression in SCI rats. The findings suggest that administration of chlorogenic acid alleviates SCI via anti‑inflammatory activity mediated by TLR4/MyD88/NF‑κB and p38 signaling pathways.