Screening of mitochondrial DNA damage repair genes in rats with septic acute kidney injury

OBJECTIVE: : To screen genes involved in mitochondrial DNA (mtDNA) damage repair in rats with septic acute kidney injury (SAKI). METHODS: : Forty male C57BL/6J mice were randomly divided into SAKI group (n=28) and sham operation group (n=12). The SAKI mouse model was established by cecal ligation and puncture. Blood and kidney samples were collected at 8, 24, and 48 h after surgery. Serum creatinine and urea nitrogen were measured by a dry biochemical analyzer. Serum inflammatory cytokines were detected by ELISA. Histopathological changes were observed with HE staining. The mtDNA damage repair related genes were screened by RNA sequencing and bioinformatics analysis; the mRNA and protein expression levels of related genes were detected by real-time quantitative RT-PCR and immunohistochemisry, respectively. RESULTS: : Symptoms of sepsis were observed in SAKI group, and 16 out of 28 mice were died in the SAKI group; serum TNF-α, IL-6, creatinine and urea nitrogen levels were higher than those in the sham group (P<0.05 or P<0.01). Histopathological examination in SAKI group showed that renal tubular epithelial cells were swollen, inflammatory cells infiltrated, and a large number of cell vacuoles were seen, suggesting successful modeling. Mitochondrial DNA damage repair related genes Gadd45α, Bcl2l1, Cdkn1a, Jun, Rela, Nfkbia and Nfkb1 were screened out. The expression of these genes was detected by real-time RT-PCR, and the results were consistent with RNA sequencing trends. Immunohistochemical staining showed that Gadd45α was mainly expressed in the nucleus of renal tubular epithelial cells, and the positive rate of Gadd45α in SAKI group was higher than that in the sham operation group (P<0.05). CONCLUSIONS: : Gadd45α, Bcl2l1, Cdkn1a, Jun, Rela, Nfkbia and Nfkb1 genes are involved in mtDNA damage repair in rats with SAKI, indicating that these genes may be used as new targets for prevention and treatment of SAKI.