Adam Właszczuk

Reduction of post-traumatic neuroma and epineural scar formation in rat sciatic nerve by application of microcrystallic chitosan

Injury of peripheral nerve is associated with the development of post‐traumatic neuroma at the end of the proximal stump, often being the origin of neuropathic pain. This type of pain is therapy‐resistant and therefore extremely nagging for patients. We examined the influence of the microcrystallic chitosan gel applied to the proximal stump of totally transected sciatic nerve on the neuroma formation and neuropathic pain development in rats. In 14 rats, right sciatic nerve was transected and the distal stump was removed to avoid spontaneous rejoining. In the chitosan (experimental) group (n = 7), the proximal stump was covered with a thin layer of the microcrystallic chitosan gel. In control animals (n = 7), the cut nerve was left unsecured. Autotomy, an animal model of neuropathic pain, was monitored daily for 20 weeks following surgery. Then, the animals were perfused transcardially and the proximal stumps of sciatic nerves were dissected and subjected to histologic evaluation. The presence, size, and characteristics of neuromas as well as extraneural fibrosis were examined. In chitosan group, the incidence and the size of the neuroma were markedly reduced, as compared with the control group; however, there was no difference in autotomy behavior between groups. In addition, extraneural fibrosis was significantly reduced in chitosan group when compared to the control group. The results demonstrate beneficial influence of microcrystallic chitosan applied to the site of nerve transection on the development of post‐traumatic neuroma and reduction of extraneural fibrosis, however without reduction of neuropathic pain.

Sciatic nerve regeneration in rats subjected to ketogenic diet.

Objectives: Ketogenic diet (KD) is a high-fat-content diet with insufficiency of carbohydrates that induces ketogenesis. Besides its anticonvulsant properties, many studies have shown its neuroprotective effect in central nervous system, but its influence on peripheral nervous system has not been studied yet. We examined the influence of KD on regeneration of peripheral nerves in adult rats. Methods: Fifty one rats were divided into three experimental (n = 15) and one control (n = 6) groups. Right sciatic nerve was crushed and animals were kept on standard (ST group) or ketogenic diet, the latter was introduced 3 weeks before (KDB group) or on the day of surgery (KDA group). Functional (CatWalk) tests were performed once a week, and morphometric (fiber density, axon diameter, and myelin thickness) analysis of the nerves was made after 6 weeks. Body weight and blood ketone bodies level were estimated at the beginning and the end of experiment. Results: Functional analysis showed no differences between groups. Morphometric evaluation showed most similarities to the healthy (uncrushed) nerves in KDB group. Nerves in ST group differed mostly from all other groups. Ketone bodies were elevated in both KD groups, while post-surgery animals’ body weight was lower as compared to ST group. Discussion: Regeneration of sciatic nerves was improved in KD – preconditioned rats. These results suggest a neuroprotective effect of KD on peripheral nerves.

The neuroprotective effect of N-acetylcysteine in spinal cord-injured rats

BACKGROUND Spinal cord injury (SCI) is an important cause of impairment of sensory and motor nerve function. It has been shown that free-radical species play an important role in the pathogenesis of acute tissue trauma after SCI. There are no proven pharmacological therapies that provide neuroprotection and stimulate axonal growth after trauma. OBJECTIVES The aim of this study was to investigate the neuroprotective effect of N-acetylcysteine (NAC) on the regeneration of spinal cord injuries in rats. MATERIAL AND METHODS A total of 20 male Wistar C rats were subjected to SCI and divided into control and experimental groups. In the control group (n = 10) trepanation and SCI by means of a pressure impactor was performed without any therapy. In the study group (n = 10), 1 dose of NAC was applied intraperitoneally (150 mg/kg b.w.) immediately after SCI, and another one after 24 h. The functional outcome on the Basso-Beattie-Bresnahan (BBB) scale and sciatic functional index (SFI) and morphological features of regeneration were analyzed during a 12-week follow-up. The spinal cords and brains were collected 12 weeks after SCI for histopathological and immunohistochemical analyses. RESULTS The rats treated with NAC presented some improvement in locomotor activity and spinal cord morphology when compared to the control group. Namely, the hind paw angle of rotation was significantly lower in the NAC group than in the control group. No differences were observed between the control and study groups in terms of interlimb coordination. The area of the main lesion was only slightly decreased in the NAC group as compared to the control group. The length of lesions in the injured spinal cord in the NAC group was diminished in comparison to the control group. The number of FG-positive cells was higher in the NAC group than in the control group. CONCLUSIONS The study showed that the neuroprotective activity of NAC had limited positive influence on the regeneration of the isolated SCI in rats.

Stent-Assisted Endovascular Treatment of Anterior Communicating Artery Aneurysms – Literature Review

Summary The anterior cerebral artery is a common location of intracranial aneurysms. The standard coil embolization technique is limited by its inability to occlude wide-neck aneurysms. Stent deployment across the aneurysm neck supports the coil mass inside the aneurysmal sac, and furthermore, has an effect on local hemodynamic and biologic changes. In this article, various management strategies and techniques as well as angiographic outcomes and complications related to stent-assisted endovascular treatment of anterior communicating artery aneurysms are presented. This treatment method is safe and associated with low morbidity and mortality rates.

The influence of spatial pulsed magnetic field application on neuropathic pain after tibial nerve transection in rat

Abstract The purpose of the study was to examine the influence of the spatial variable magnetic field (induction: 150–300 µT, 80–150 µT, 20–80 µT; frequency 40 Hz) on neuropathic pain after tibial nerve transection. The experiments were carried out on 64 male Wistar C rats. The exposure of animals to magnetic field was performed 1 d/20 min., 5 d/week, for 28 d. Behavioural tests assessing the intensity of allodynia and sensitivity to mechanical and thermal stimuli were conducted 1 d prior to surgery and 3, 7, 14, 21 and 28 d after the surgery. The extent of autotomy was examined. Histological and immunohistochemical analysis was performed. The use of extremely low-frequency magnetic fields of minimal induction values (20–80 µT/40 Hz) decreased pain in rats after nerve transection. The nociceptive sensitivity of healthy rats was not changed following the exposition to the spatial magnetic field of the low frequency. The results of histological and immunohistochemical investigations confirm those findings. Our results indicate that extremely low-frequency magnetic field may be useful in the neuropathic pain therapy.