Pokazatelji oštećenja i oporavka u različitim moždanim regijama i vremenskim intervalima nakon traumatske ozljede mozga u štakora

doctoral thesis

• Title (english): Parameters of the brain damage and repair in different traumatic brain injury in rats : Parameters of the brain damage and repair in different regions and time points following traumatic brain injury in rats
• Author: Dolenec Petra
• Mentor: Gordana Župan (mentor); MBZ: 142160
• Committee member: Dubravka Švob Štrac (predsjednik povjerenstva)
• Committee member: Zoran Tadić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2017, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology
• Universal decimal classification (UDC): 57 - Biological sciences. Physical anthropology. Biodiversity

Abstract

U ovom doktorskom radu proučavani su opseg i vrijeme pojave pokazatelja oštećenja i
oporavka posljedično traumatskoj ozljedi mozga (engl. traumatic brain injury, TBI) u dosad
nedovoljno istraženim regijama mozga (talamus, mali mozak, rostralni dio velikog mozga).
Pokusi su rađeni na odraslim Hannover-Wistar štakorima muškog spola. TBI je inducirana
metodom lateralne ozljede mozga tlakom tekućine. Štakori su žrtvovani prvog, trećeg ili
sedmog dana nakon TBI, a kontrolnu skupinu činile su životinje žrtvovane prvog dana nakon
lažne ozljede. Uzorci mozgova proučavani su Western blot i TUNEL metodama,
histološkim/imunohistološkim analizama te Fluoro-Jade B bojenjem. U talamusu ozlijeđenih
životinja pronađene su progresivna degeneracija i gubitak neurona, programirana stanična smrt
neovisna o aktivnoj kaspazi-3, a posredovana čimbenikom indukcije apoptoze (AIF), reaktivna
astrocitoza i mikroglioza, te ograničene neuroplastične promjene tijekom prvog tjedna nakon
TBI. U malom mozgu ozlijeđenih štakora, prvog dana nakon TBI, neurodegenerativne
promjene zabilježene su u stražnjim režnjićima, a potom su ponovno uočene sedmog dana
nakon traume u širem području ove strukture. U IX. režnjiću bio je detektiran i značajan gubitak
Purkinjeovih stanica u svim istraživanim vremenskim točkama. Najjače izražena apoptoza, koja
nije bila posredovana aktivacijom kaspaze-3 niti AIF-om, zabilježena je prvog dana nakon
ozljede u svim slojevima kore IX. režnjića. Pojačani AIF signal pronađen je u bijeloj tvari
malog mozga trećeg i sedmog dana nakon TBI. Iako su ekspresije markera astrocita i mikroglije
bile smanjene u ipsilateralnoj polovici malog mozga nakon TBI, na mjestima oštećenja
Purkinjeovih stanica zabilježena je njihova aktivacija. Diskretne neuroplastične promjene
nakon TBI detektirane su u IX. režnjiću. U strukturama rostralnog dijela velikog mozga
degeneracija i gubitak neurona nisu zabilježeni u prvom tjednu nakon TBI. U frontalnom
korteksu ozlijeđenih štakora pronađene su reaktivna astrocitoza i mikroglioza, te stanice
pozitivne na DCX, marker neuroblasta, a neuroplastične promjene nisu uočene. Promjene
imunoreaktivnosti DCX-a detektirane su i u subventrikularnoj zoni i rostralnom migratornom
putu ozlijeđenih životinja. Sumarno, rezultati ovog rada pokazali su kako TBI u štakora
uzrokuje pojavu znakova oštećenja i oporavka u istraživanim moždanim strukturama u
različitim vremenskim točkama tijekom prvog tjedna nakon ozljede.

Abstract (english)

In this doctoral thesis regional and temporal distribution of the parameters of damage and
repair following traumatic brain injury (TBI) were investigated in the rat brain structures which
have not been previously studied extensively (thalamus, cerebellum, rostral part of the
cerebrum). Experiments were done on adult male Hannover-Wistar rats. TBI was induced by
lateral fluid percussion injury method. Rats were sacrificed on the first, third or seventh day
after TBI, and the rats sacrificed on the first day after sham injury were used as the control
group. Brain samples were examined by Western blot and TUNEL methods,
histologic/immunohistologic analyses, and by Fluoro-Jade B staining. In the thalamus of
injured animals progressive degeneration and neuronal loss, programmed cell death, which was
caspase-independent, but mediated by apoptosis inducing factor (AIF), reactive astrocytosis
and microgliosis as well as limited neuroplastic changes were detected during the first week
after TBI. In the cerebellum of the injured rats, on the first day after TBI, neurodegenerative
changes were discovered in the posterior lobules, and on the seventh day after brain trauma,
diffusely through this brain structure. In the lobule IX, a significant loss of Purkinje cells was
detected at all the investigated time points. Most significant apoptosis, which was caspase-3
and AIF independent, was found on the first post-injury day in all the cortical layers within the
lobule IX. Enhanced AIF signal was detected in the cerebellar white matter on the third and
seventh day after TBI. Even though the expressions of astrocytic and microglial markers were
lower in the ipsilateral halves of the cerebellum after TBI, activation of these cells was
discovered in the areas of pronounced Purkinje cells’ loss. Discrete neuroplastic changes after
TBI were also detected in the lobule IX. In the structures of the rostral part of the cerebrum,
degeneration and neuronal loss were not detected in the first week after TBI. In the frontal
cortex of the injured animals reactive astrocytosis and microgliosis were found as well as the
cells which expressed DCX, a neuroblast marker, while other neuroplastic changes were not
revealed. Changes in the DCX immunoreactivity were also detected in the subventricular zone
and the rostral migratory stream in the injured animals. In conclusion, results of this thesis
demonstrated that TBI in the rat causes appearance of the sings of damage and repair in the
investigated brain structures in different time points within the first week after the injury.

• Keywords: traumatska ozljeda mozga; patofiziologija; talamus; mali mozak; rostralni dio velikog mozga; štakor
• Keywords (english): traumatic brain injury; pathophysiology; thalamus; cerebellum; rostral part of the cerebrum; rat
• Language: croatian
• URN:NBN: urn:nbn:hr:217:863820
• Study programme: Title: Biology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija (doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2019-12-31
• Created on: 2017-07-06 10:26:29