NEC-1 ATTENUATES MITOCHONDRIAL DAMAGE IN THE RENAL TUBULAR EPITHELIAL CELLS OF MICE WITH URINARY SEPSIS BY UPREGULATING PGC1-Α TRANSCRIPTION

Yanya Lin¹, Jianxiong Hu¹, Jianhui Chen¹, Shijun Chen¹, Yangfang Cai¹, Chengda Lin^2*

¹Department of Critical Care Medicine, Affiliated Hospital of Putian University, Putian 351100, Fujian Province, China - ²Department of Neurosurgery, Putian Medical District, 900th Hospital of the Joint Logistics Support Force of the Chinese People's Liberation Army, Putian 351100, Fujian Province, China

Objective: To investigate the effect and mechanism of Nec-1 on mitochondrial damage in the renal tubular epithelial cells of septic mice by upregulating the transcription of peroxisome proliferator-activated receptor γ costimulatory factor (PGC1-α). 

Methods: A total of 18 C57BL/6 mice were randomly and equally divided into a normal control group, an LPS group and an LPS+Nec-1 group. The mice in the normal control group were injected with 10 mL·kg-1 sterile water; the mice in the LPS group were injected with 10 mL·kg-1 LPS intraperitoneally; and the mice in the LPS+Nec-1 group were injected with 1.65 mL·kg-1 NEC followed by 10 mL·kg-1 LPS. After 18 hours, blood was collected from the inferior vena cava and both kidneys, and the levels of serum creatinine, urinary nitrogen, PGC1-α protein and mRNA expression were compared. The HK-2 cells were randomly divided into a normal control group, an LPS group and an LPS+Nec-1 group after conventional culture and passage. The cells in the normal control group were treated with 10 μ g·ml-1 LPS for 18 h, the cells in the LPS+Nec-1 group were pre-treated with 50 μg·ml-1 Nec-1 for 6 h, and then treated with 10 μg·ml-1 LPS for 18 h. The morphological changes of mitochondria were observed. 

Results: Compared with the normal control group, the levels of serum creatinine and urinary nitrogen in the mice in the LPS group increased significantly (P<0.05), while the levels of serum creatinine and urinary nitrogen in the LPS+Nec-1 group decreased significantly compared with the LPS group (P<0.05). The epithelial structure of the renal tubules in the normal control mice did not change significantly. The number of mitochondria in the renal tubule epithelial cells of mice in the LPS group decreased significantly, and mitochondrial swelling and vacuolation was also observed. In addition, no mitochondrial crests were observed. The degree of mitochondrial swelling in the renal tubular epithelial cells of the mice in the LPS+Nec-1 group was minor: the number of mitochondria did not change significantly and no mitochondrial vacuolation or mitochondrial crest disappearance was observed. Compared with the normal control group, the protein and mRNA expression levels of PGC1-α in the renal tissue of mice in the LPS group decreased significantly (P<0.05), while the protein and mRNA expression levels of PGC1-α in the renal tissue of mice in the LPS+Nec-1 group significantly increased (P<0.05). 

Conclusion: Nec-1 can reduce mitochondrial damage in the renal tubular epithelial cells of septic mice, and has a protective renal function, which may be achieved by upregulating PGC1-α transcription.