Title: Dynamic changes of mitochondrial function at different stages of myocardial injury in sepsis model rats
Abstract: Objective To explore the changes of mitochondrial function at different stages of myocardial injury in sepsis rats induced by lipopolysaccharide (LPS). Methods A total of 32 SD male SPF rats were randomly divided into 4 groups (8 each): control group (control), sepsis 6h group (LPS-6h), 12h group (LPS-12h), and 24h group (LPS-24h). Rats in control group had been administrated with saline solution using intraperitoneal (i.p.) injection. To establish the sepsis model, rats in the rest three groups received LPS at the dosage of 10mg/kg by i.p. injection. At 6, 12 and 24h after LPS injection, blood samples were collected from cardiac apex after anesthesia promptly, and myocardial tissues were clipped followed by frozen at –80℃ immediately. The collected blood samples were tested by a fully automatic chemical immunoassay to detect hypersensitive cardiac troponin I (hs-cTnI). The expression of caspase-3, Bcl-2 and Bax protein in myocardial tissues were tested by Western blotting, and the ratio of Bcl-2 over Bax was calculated. ATP content and cytochrome C oxidase (COX) activity in myocardial tissues were measured by the spectrophotometer. Results The serum hs-cTnI in each group was statistically significantly different (F=394.63, P=0.000), with higher levels in sepsis groups than that in control group, and the highest levels were detected in LPS-24h group. The expression levels of caspase-3 and Bax, both of which are pro-apoptosis factors, was statistically significant upregulated in LPS-12h and LPS- 24h groups compared with control group (P<0.05), with a fashion to increase over time. The expression levels of Bcl-2 in LPS-12h and LPS-24h groups were significantly lower than that in control group (PP<0.050.01), and the lowest level was detected in LPS-24h group. The ratio of Bcl-2/Bax was significantly lower in LPS-24h group than in control group. The ATP content in each group was statistically significant (F=152.71, P=0.000), and decreased in sepsis groups, with the least level detected in the LPS-24h group. The COX activity in each group was statistically significant (F=131.52, P=0.000), and decreased in each sepsis group (P<0.05), with the lowest activity in the LPS-24h group. Conclusion In the sepsis rats induced by LPS, it is possible that the activation of apoptosis-related genes would inhibit the activity of COX in the mitochondria, leading to the reduced production of ATP, which would further aggravate the myocardial damage.
DOI: 10.11855/j.issn.0577-7402.2018.10.07
Publication Year: 2018
Publication Date: 2018-10-01
Language: en
Type: article
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