[Influence of diazoxide on mitochondrial apoptosis in human renal tubular cells induced by serum obtained from neonates with asphyxia].
OBJECTIVE
To study the influence of diazoxide on mitochondrial apoptosis pathway of human renal proximal tubular cells (HK-2 cells).


METHODS
Cultured HK-2 cells were inoculated on 6-well plates, according to stochastic tables law, and they were divided into normal serum-treated group (NSTG) , post-asphyxial serum treatment group (PSTG), and post-asphyxial serum and diazoxide treatment group (PSDTG). The serum from neonates 24 hours after asphyxia in a dilution of 20% (volume fraction) was used for challenge. Diazoxide in a final concentration of 100 mol/L, was used for intervention. The expression of caspase-3 was detected by immunohistochemical method. The translocation rate of Omi/HtrA2 and mitochondria membrane potential were determined by indirect immunofluorescence and confocal microscopy.


RESULTS
Compared with that of NSTG, the expression of caspase-3 absorbance (A) value of HK-2 cells in PSTG was significantly increased (25.19 + or - 3.33 vs. 13.63 + or - 1.89, P<0.01), the translocation rate of Omi/HtrA2 of HK-2 cells in PSTG was significantly increased [(56.01 + or - 5.30)% vs.(37.59 + or - 5.60)%, P<0.01], mitochondrial membrane red/green fluorescence intensity ratio was decreased significantly (0.79 + or - 1.42 vs. 1.82 + or - 0.23, P<0.01). Compared with the PSTG, the expression value of caspase-3 of HK-2 cells in PSDTG was significantly decreased (20.17 + or - 2.19), the translocation rate of Omi/HtrA2 of HK-2 cells in PSDTG was significantly decreased [(46.91 + or - 2.70)%], and mitochondrial membrane red/green fluorescence intensity ratio increased significantly (1.47 + or - 0.14), but did not recover to the same degree as that of the NSTG (all P<0.01).


CONCLUSIONS
The diazoxide may reduce the expression of caspase-3, intracellular translocation of Omi/HtrA2, and stability of mitochondrial membrane potential, thereby significantly alleviates HK-2 cells injury induced by post-asphyxial-serum of neonate.
Liu
Xi-juan
XJ
Department of Neonatology, Affiliated Hospital of Luzhou Medical College, Luzhou 646000, Sichuan, China.
Dong
Wen-bin
WB
Li
Qing-ping
QP
Lei
Xiao-ping
XP
Zhai
Xue-song
XS
Xiong
Tao
T
Deng
Cun-liang
CL
Chen
Feng
F
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001238:Asphyxia Neonatorum / Q000097:blood*; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D003981:Diazoxide / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D000074923:High-Temperature Requirement A Serine Peptidase 2; D006801:Humans; D007231:Infant, Newborn; D007687:Kidney Tubules, Proximal / Q000166:cytology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000378:metabolism* / Q000502:physiology; D024101:Mitochondrial Proteins / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D012697:Serine Endopeptidases / Q000378:metabolism; D044967:Serum
D024101:Mitochondrial Proteins; D012697:Serine Endopeptidases; C000615914:HTRA2 protein, human; D000074923:High-Temperature Requirement A Serine Peptidase 2; C505407:CASP3 protein, human; D053148:Caspase 3; D003981:Diazoxide