ABSTRACT
Objective:To explore the expression features of cytochrome C oxidase subunit Ⅰ (MT-CO1), BCL2 interacting protein 3 (BNIP3) and interleukin (IL)-1β in the liver of MRL/lpr lupus mice.Methods:The mRNA and protein levels of MT-CO1, BNIP3, IL-1β, p16 and p21 in lupus mice and control mice were detected by polymerase chain reaction (PCR) and Western blot, the IL-1β expression site were detected by hematoxylin and eosin (HE) staining and immunohistochemical method, and themalondialdehyde (MDA) was detected by colorimetry. Hepatocytes and macrophages were stimulated with lipopolysaccharide (LPS), while hepatocytes were also cultured with supernatants obtained after macrophages stimulated with LPS, and the mRNA and protein levels of MT-CO1, BNIP3 and LC3B, as well as p16 and p21 expression, were determined by qPCR and Western blot. The expression of mitochondrial reactive oxygen species (mtROS) was detected by immunofluorescence. One way Analysis of Variance (ANOVA) was used to compare the mean of each group, and LSD method was used to compare the means of multiple samples, and Tamhane's T2 method was used to compare the means of multiple samples when the variance was uniform. Results:The results of PCR showed that the mRNA levels of MT-CO1 and BNIP3 in the liver tissue of the lupus group (0.14±0.04; 0.16±0.05) were significantly lower than those of the control group (0.11±0.04; 0.16±0.06), and the differences were statistically significant ( t=7.16, P<0.001; t=4.54, P<0.001). The expression levels of IL-1β, p16 and p21 in the lupus group (2.06±0.69; 0.37±0.14; 0.16±0.06) were significantly higher than those of the control group (0.23±0.06; 0.25±0.08; 0.11±0.04) ( t=9.58, P<0.001; t=24.35, P<0.001; t=22.36, P<0.001). The results of Western blot were consistent with those of PCR. HE staining showed lymphocyte infiltration in the liver tissue of lupus mice, and immunohistochemistry showed IL-1β in the liver tissue of lupus mice. The positive cells were mainly concentrated in the sinusoids, and the expression of hepatic parenchymal cells was not rearkable. The content of MDA in liver tissue of the lupus group (0.19±0.10) was higher than that of the control group (0.17±0.09), and the difference was statistically significant ( t=4.33, P=0.005). LPS directly stimulated AML12 hepatocytes (0.069±0.028; 0.17±0.07). The PCR results showed that compared with the control group (0.176±0.072; 0.08±0.03), the expression of MT-CO1, and BNIP3 were not significantly different ( t=1.01, P=0.337; t=0.88, P=0.399). The expression of IL-1β was significantly higher when incubated with the supernatants of LPS stimulated macrophages (0.28±0.09) compared than that of the control group (0.15±0.05) ( t=28.26, P<0.001). The results of PCR showed that the mRNA levels of MT-CO1 and BNIP3 in the LPS stimulated group (0.046±0.026; 0.17±0.05) were significantly lower than those in the control group (0.143±0.083; 0.18±0.06), and the differences were statistically significant ( t=7.52, P<0.001; t=4.24, P<0.001), The expression of p16 and p21 in LPS stimulated group (0.29±0.09; 0.27±0.09) were significantly higher than those in the control group (0.18±0.06; 0.22±0.07) ( t=13.54, P<0.001; t=8.69, P<0.001). The results of Western blot were consistent with those of PCR. Immunofluorescence showed that the fluorescence intensity of mtROS in LPS stimulated group (0.25±0.10) was higher than that in the control group (0.08±0.03), and the difference was statistically significant ( t= 4.86, P<0.001). Conclusion:Immune-mediated inflammation in the liver tissue of lupus mice can stimulate liver parenchymal cells to cause intracellular mitochondrial dysfunction. However, the mechanism of liver organ damage in lupus mice is not limited to the immune-mediated inflammation of immune active cells, but also include parenchymal cell mitochondrial dysfunction.