Study On Fastigial Nucleus’s Morphological Changes And Its Mechanism Of Injury In Rats With Post-Stroke Depression

ObjectiveThe main purposes of our study are to observe the morphological changesof fastigial nucleus in rats with PSD (post-stroke depression, PSD), as well asthe expressions of apoptotic neurons in this region. We also try to explorepreliminarily the underlying mechanism of impairment of the fastigial nucleus byobserving the expressions of apoptosis-related proteins caspase-3, caspase-8,caspase-9and AIF (apoptosis-inducing factor, AIF) in this region, so as toexplore the relationship between the lesions of fastigial nucleus and the onset ofPSD.MethodsHealthy SD rats were randomly divided into four groups. The control group(Sham operated models were given the sham treatment). The stroke group(Stroke models were set up by blocking the middle cerebral artery). Thedepression group (Depression models were induced by separately raised andput into chronic unpredictable mild stress (chronic unpredictable mild stress,CUMS)) and The PSD group (PSD models were induced by separately raisedand put into CUMS after blocking the middle cerebral artery. After the test ofbehavioral scores, the brain tissue specimens were collected after decapitation.Morphological changes of fastigial nucleus were detected by Nissl staining.Apoptosis were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (Terminal deoxynucleotidyl transferase-mediated dUTPnick end labeling, TUNEL). Apoptosis-related proteins caspase-3, caspase-8,caspase-9and AIF were detected by immunohistochemisty.Results1. The observation of behavioral scores in rats: The results showed that thegrowth rate of body weight, the sugar consumption, the scores of horizontalmovement and vertical movement decreased and the fixed time inforced-swimming test was prolonged significantly compared with the controlgroup.2. The observation of morphological changes of fastigial nucleus: In thecontrol group, the cells with clear outline and the structures were compact, cellswere big and abundant and Nissl bodies were stained evenly in the cytoplasm.In PSD group, Nissl body generally declined or even disappeared. Nissl body inother groups declined with different degree.3. TUNEL assay: The numbers of TUNEL positive neurons were seenaccidentally in the sham operated group, which may be related to thephysiological death. While, the number of TUNEL positive neurons haveincreased significantly in other groups compared with the control group (p0.05or p0.01), and the PSD group showed the highest level of TUNEL positiveneuron (p0.01).4. Immunohistochemisty results: The expressions of caspase-3, caspase-8,caspase-9and AIF were significant lower in the control group than that in PSDgroup (p0.05).Conclusions1. There are some lesions located on the region of fastigial nucleus in ratswith PSD, which may have a relationship with the onset of PSD.2. The damage of fastigial nucleus in rats with PSD may have a relationshipwith apoptosis, which can be conducted by the caspase-dependent pathway and caspase-independent pathway, but the exact pathways remain unknown.