Antioxidation and anti-inflammation by haem oxygenase-1 contribute to protection by tetramethylpyrazine against gentamicin-induced apoptosis in murine renal tubular cells.
BACKGROUND
Gentamicin, a widely used antibiotic for the treatment of bacterial infection, can cause nephrotoxicity. Tetramethylpyrazine (TMP) is a compound purified from the rhizome of Ligusticum wallichi (called chuanxiong in Chinese). Besides its protection against ischaemia-reperfusion injury and nephritis in mice, we previously reported that TMP reverses gentamicin-induced apoptosis in rat kidneys. Haem oxygenase-1 (HO-1) induction by TMP has also been shown to attenuate myocardial ischaemia/reperfusion injury in rats.


METHODS
We used rat renal tubular (NRK-52E) cells, transformed cells with HO-1 overexpression or knockdown, and an adenovirus carrying the HO-1 gene (Adv-HO-1) as gene therapy targeting murine kidneys to explore the role of HO-1 in protection by TMP against gentamicin-induced toxicity both in vitro and in vivo. We evaluated the protective effects of HO-1 on several apoptotic parameters induced by gentamicin: cleaved caspases-3 and -9, cycloxygenase-2 (Cox-2) and subcellular localization of nuclear factor kappa B-p65 (NF-kappaB-p65), Bcl-xl and HS-1-associated protein (Hax-1) in NRK-52E cells.


RESULTS
NRK-52E cells treated with TMP exhibited transcriptional upregulation of the HO-1 protein by approximately twofold. Overexpression of HO-1 in NRK-52E cells significantly increased mitochondrial protein levels of the antiapoptotic molecules, Bcl-xL and Hax-1, and markedly decreased the NADPH oxidase activity and proinflammatory molecules, NF-kappaB-p65 and Cox-2, which might decrease gentamicin-induced activation of caspases-9 and -3. Conversely, NRK-52E cells with HO-1 knockdown significantly exacerbated gentamicin-induced tubular cell apoptosis. Additionally, the concomitant HO-1 induction by TMP was also evident in vivo, and HO-1 therapy markedly attenuated gentamicin-induced renal apoptosis to a similar extent as TMP pretreatment.


CONCLUSIONS
Collectively, we suggest that HO-1 induced by TMP might, at least in part, protect against gentamicin-induced nephrotoxicity through antiapoptotic and anti-inflammatory mechanisms, and that it may have therapeutic potential for patients with renal disease. This is also the first demonstration that HO-1 increases Hax-1 mitochondrial localization.
1Department of Nephrology, Taipei Medical University, Wan Fang Hospital, Taipei, Taiwan.
Yuh-Mou
YM
Sue
Ching-Feng
CF
Cheng
Chih-Cheng
CC
Chang
Ying
Y
Chou
Cheng-Hsien
CH
Chen
Shu-Hui
SH
Juan
D000818:Animals; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005839:Gentamicins / Q000009:adverse effects*; D051547:Heme Oxygenase-1 / Q000502:physiology*; D007673:Kidney Cortex Necrosis / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology; D007684:Kidney Tubules / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D011719:Pyrazines / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D014665:Vasodilator Agents / Q000494:pharmacology* / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D051017:Apoptosis Regulatory Proteins; D005839:Gentamicins; D011719:Pyrazines; D014665:Vasodilator Agents; D051547:Heme Oxygenase-1; C017953:tetramethylpyrazine