Distribucija botulinum toksina tipa A u mozgu štakora nakon periferne primjene

master's thesis

• Title (english): The distribution of botulinum toxin type A in the rat brain after peripheral application
• Author: Mihael Grdunac
• Mentor: Lidija Bach-Rojecky (mentor)
• Committee member: Lidija Bach-Rojecky (predsjednik povjerenstva)
• Committee member: Anita Hafner (član povjerenstva)
• Committee member: Maja Bival Štefan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of pharmacology); Zagreb
• Defense date and country: 2024, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Pharmacy

Abstract

Iako predstavlja najpotentniji otrov poznat čovječanstvu, botulinum toksin tipa A (BT-A) tijekom posljednjih 30-ak godina pronašao je svoje mjesto u terapiji različitih stanja praćenih mišićom hiperkontraktilnošću. Novija ispitivanja ukazala su na njegov antinociceptivni učinak, pri čemu kronična migrena predstavlja prvu bolnu indikaciju za koju je odobren. Osim migrene, pokazuje veliki potencijal i u terapiji različitih vrsta neuropatske boli. Uz terapijsku primjenu, postao je i neizostavni dio u suvremenoj estetskoj medicini, te jedan od globalno najpopularnijih estetskih zahvata, pri čemu je smatran kao siguran i bez ozbiljnih štetnih nuspojava. Dokazi o među-sinaptičkom transportu BT-A u vizualnom, motornom i senzornom sustavu dodatno su potvrdili hipotezu o središnjem mehanizmu djelovanja na bol, s obzirom da BT-A retroaksonalnim transportom s periferije dolazi do prve sinapse unutar leđne moždine, gdje interferira s različitim neurotransmiterskim sustavima. Stoga, postavlja se pitanje ostaje li BT-A na razini leđne moždine ili se transinaptičkim prijenosom prenosi dalje u supraspinalne regije. Cilj ovog istraživanja bilo je ispitati distribuciju BT-A unutar hipotalamusa, hipokampusa, gracilne te facijalne jezgre, nakon jednostrane periferne primjene u stražnju šapu štakora. Imunohistokemijskom metodom praćen je indirektni pokazatelj proteolitičke aktivnosti BT-A, pokidani fragment SNAP-25 proteina. Signal pokidanog SNAP-25 detektiran je unutar svih promatranih regija, pri čemu je kod skupine kojoj je primijenjen specifičan antitoksin za BT-A, uočeno smanjenje intenziteta signala. Taj učinak rezultat je neutralizacije dijela izvanstaničnog BT-A antitoksinom te indirektni dokaz među-sinaptičkog prijenosa BT-A u središnjem živčanom sustavu. Prikazani rezultati otvaraju brojna pitanja o značenju ovih nalaza, posebice u kontekstu sigurnosti dugotrajne primjene BT-A, te zahtijevaju daljnja ispitivanja.

Abstract (english)

Although it represents the most potent toxin known to humanity, botulinum toxin type A (BT-A) has found its place over the last 30 years in the therapy of various conditions accompanied by muscle hypercontractility. Recent studies have indicated its antinociceptive effect, with the first case of approval as treatment for chronic migraine. Besides migraine, it shows great potential in the therapy of various types of neuropathic pain. In addition to therapeutic use, it has also become an indispensable part of modern aesthetic medicine and one of the most popular aesthetic procedures, generally being accepted as safe and without serious adverse side effects. Evidence of BT-A's trans-synaptic transport in the visual, motor, and sensory systems has further confirmed the hypothesis of a central mechanism of action on pain, given that BT-A reaches the first synapse within the spinal cord through retroaxonal transport from the periphery, where it interferes with various neurotransmitter systems. Therefore, the question arises whether BT-A remains at the spinal cord level or is transported trans-synaptically to supraspinal regions. The aim of this research was to examine the distribution of BT-A within the hypothalamus, hippocampus, gracile, and facial nuclei after unilateral peripheral administration to the hind paw of rats. The immunohistochemical method tracked an indirect indicator of BT-A proteolytic activity, the cleaved fragment of the SNAP-25 protein. The signal of cleaved SNAP-25 was detected within all observed regions, with a reduction in signal intensity noted in the group treated with a specific antitoxin for BT-A. This effect is the result of the neutralization of a part of extracellular BT-A by the antitoxin and an indirect proof of BT-A trans-synaptic transport in the central nervous system. The presented results raise numerous questions about the significance of these findings, especially in the context of the safety of long-term BT-A use, and require further investigation.

• Keywords: botulinum toksin; antitoksin; SNAP-25; transcitoza; imunohistokemija; gracilna jezgra; facijalna jezgra; hipotalamus; hipokampus
• Keywords (english): botulinum toxin; antitoxin; SNAP-25; transcytosis; immunohystochemistry; gracile nucleus; facial nucleus; hypothalamus; hippocampus
• Language: croatian
• URN:NBN: urn:nbn:hr:163:211550
• Study programme: Title: Pharmacy - integrated undergraduate and graduate - university study; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: sveučilišni magistar farmacije (sveučilišni magistar farmacije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2026-07-10
• Created on: 2024-07-26 08:21:36