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Involvement of reactive oxygen species on gentamicin-induced mesangial cell activation
Carlos Martínez-Salgado1, Nélida Eleno, Paula Tavares
1Departamento de Fisiología y Farmacología and Instituto Reina Sofía de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.
Background:
Reactive oxygen species (ROS) have been shown to be involved in the reduction of glomerular filtration rate observed after gentamicin (Genta) treatment in vivo, a phenomenon directly related with mesangial cell (MC) contraction. Our previous study reported that Genta induces concentration-dependent MC contraction and proliferation in vitro.
Methods:
To study the possible mediation of ROS in the effect of Genta, ROS production was measured in primary cultures of rat MC stimulated with Genta (10-5 mol/L). In addition, the MC response to Genta in the presence of the ROS scavengers superoxide dismutase (SOD) and catalase (CAT) was studied. MC activation and O2- production were studied in the presence of an inhibitor of the NADP(H) oxidase, diphenylene iodinium (DPI), and in the presence of L-NAME, an inhibitor of nitric oxide synthases (NOS). Finally, the effects of Genta on SOD activity and mRNA expression were examined.
Results:
Genta (10-5 mol/L) induced an increase in O2- production and SOD activity that was neither accompanied by an elevation in cytosolic Cu/Zn-SOD mRNA expression nor by H2O2 accumulation. Genta induced MC contraction and proliferation that were inhibited by SOD plus CAT. Both the extracellular and intracellular ROS donor systems, xantine+xantine oxidase (X+XO) and dimethoxinaphtoquinone (DMNQ), respectively, also stimulated MC contraction and proliferation. Genta-induced MC activation and O2- production were inhibited by DPI. Genta-induced O2- production was inhibited by L-NAME. Furthermore, Genta did not induce detectable changes in membrane fluidity and lipid peroxidation.
Conclusions:
These results strongly suggest that an oxidative-mediated pathway exists in Genta-induced MC activation. A portion of the production of O2- may be due to NADP(H) oxidase and NOS activation. The amount of ROS produced, rather than having a toxic effect, might play a role as a mediator of Genta-induced MC activation
Insights
Gentamicin (Genta) causes kidney damage by activating mesangial cells (MC) through reactive oxygen species (ROS). This study shows ROS mediate Genta
Area of Science:
- Nephrology
- Cell Biology
- Biochemistry
Background:
- Gentamicin (Genta) treatment reduces glomerular filtration rate, linked to mesangial cell (MC) contraction.
- Previous studies show Genta induces concentration-dependent MC contraction and proliferation in vitro.
Purpose of the Study:
- To investigate the role of reactive oxygen species (ROS) in mediating gentamicin-induced mesangial cell activation.
- To explore the involvement of NADP(H) oxidase and nitric oxide synthases (NOS) in Genta's effects.
Main Methods:
- Measured ROS production in rat MC cultures stimulated with Genta.
- Assessed MC response to Genta with ROS scavengers (superoxide dismutase, catalase) and inhibitors (DPI, L-NAME).
- Examined Genta's effects on SOD activity and mRNA expression.
Main Results:
- Genta increased O2- production and SOD activity in MCs.
- Genta-induced MC contraction and proliferation were inhibited by SOD plus catalase.
- ROS donors mimicked Genta's effects on MCs, and Genta-induced O2- production was inhibited by DPI and L-NAME.
Conclusions:
- An oxidative-mediated pathway is involved in Genta-induced MC activation.
- NADP(H) oxidase and NOS activation contribute to Genta-induced O2- production.
- ROS act as mediators, rather than solely toxic agents, in Genta-induced MC activation.