ABSTRACT
Objective:To explore the role and mechanism of tubastatin A (TubA) in alleviating brain injury after cardiac arrest and cardiopulmonary resuscitation (CA-CPR) by inhibiting endoplasmic reticulum stress-mediated cell apoptosis in swine.Methods:Twenty-three conventional male white swine, weighing 33-40 kg, aged 4 to 6 months, were divided into 3 groups by random number table method: sham group ( n=6), CA-CPR group ( n=9), and TubA group ( n=8). The CA-CPR swine model was established by 9 min of electrically induced CA through pacing catheter in the right ventricle and then 6 min of CPR in the CA-CPR group. The CA-CPR swine model was established by the same method, and then a dose of 4.5 mg/kg of TubA at 5 min after resuscitation was intravenously infused in the TubA group. The serum concentrations of neuron specific enolase (NSE) and S100β protein (S100β) were measured using ELISA before modeling and at 1, 2, 4 and 24 h after resuscitation. Neurological deficit score (NDS) was evaluated at 24 h after resuscitation. Thereafter, the animals were euthanized, and brain cortex tissues were harvested, and the expression levels of caspase-12 and caspase-3 were measured using immunohistochemistry. Cell apoptosis index was detected by TUNEL assay. The variables among the three groups were compared with one-way analysis of variance and the Bonferroni hoc test using SPSS software. Results:Twenty-four h after resuscitation, the serum concentrations of NSE and S100β were significantly increased, and NDS was markedly elevated in the CA-CPR and TubA groups compared with the sham group (all P<0.05). Compared with the CA-CPR group, serum concentration of NSE starting 2 h after resuscitation and serum concentration of S100β starting 1 h after resuscitation were significantly decreased in the TubA group [NSE (ng/mL): (23.1±2.0) vs. (20.2±2.0) at 2 h, (28.4±2.3) vs. (23.7±1.9) at 4 h, (32.1±2.7) vs. (26.6±2.0) at 24 h; S100β (pg/mL): (2239±193) vs. (1923±101) at 1 h, (2817±157) vs. (2360±141) at 2 h, (3384±250) vs. (2691±210) at 4 h, (3965±303) vs. (3119±260) at 24 h, all P<0.05], and NDS was markedly reduced (240±30 vs. 63±44, P<0.05). At 24 h after resuscitation, brain cortex tissue detection showed that the expression levels of caspase-12 and caspase-3 were significantly increased, and cell apoptosis index was markedly elevated in the CA-CPR and TubA groups compared with the sham group (all P<0.05). However, the expression levels of caspase-12 and caspase-3 were significantly decreased [caspase-12:(7.1±0.7) vs. (4.2±0.4); caspase-3: (13.3±1.6) vs. (7.7±0.8), all P<0.05], and cell apoptosis index was markedly reduced in the TubA group compared to the CA-CPR group [(31.1±8.6) vs. (17.3±2.2), P<0.05]. Conclusions:TubA alleviates brain injury and neurological dysfunction after CA-CPR in swine, which may be related to the inhibition of cell apoptosis mediated by endoplasmic reticulum stress.
ABSTRACT
Many surface proteins of Gram-positive bacteria are anchored to the cell wall by the action of sortase enzymes, a recently discovered family of cysteine transpeptidases. As the surface proteins of pathogens are frequently required for virulence, the sortase might be a suitable target for the development of anti-Gram-positive drugs. Recently, the mechanism and active sites of sortase was elucidated by the research of sortaseA(SrtA) in Staphylococcus aureus and a series of SrtA inhibitors have been identified for providing the basis for further development of potent inhibitors.