Clonidine ameliorates cisplatin-induced nephrotoxicity: impact on OCT2 and p38 MAPK pathway.

OBJECTIVES: To explore clonidine (Clon) nephroprotective effects as an inhibitor of organic cationic transporter 2 (OCT2) and p38 mitogen-activated protein kinase (p38 MAPK) against cisplatin (CP)-induced nephrotoxicity. OCT2 is mainly responsible for renal accumulation of CP. Clon has been recently recognized as an OCT2 inhibitor and exerts beneficial effects on renal function and p38 MAPK. This study further investigates its underlying anti-inflammatory, antioxidative and antiapoptotic effects. METHODS: Rats were randomly assigned into five groups: (I) CON, (II) CP, (III) CP + Clon 0.125, (IV) CP + Clon 0.25, (V) CP + Clon 0.5, and (VI) Clon 0.5 alone. Clon was administered orally at 0.125, 0.25 and 0.5 mg/kg/day dosages for 10 days. On day 7, rats in groups from (II) to (V) received a single intraperitoneal injection of CP (10 mg/kg). KEY FINDINGS: Clon 0.25 mg/kg displayed the best nephroprotective outcomes, justified by the significant amelioration of parameters like renal function, oxidative stress, and inflammatory status, as well as modulated the OCT2 expression, phosphorylation of p38 and p53, compared with Clon 0.125 and 0.5 mg/kg. CONCLUSION: This study suggests the promising nephroprotective impact of Clon as an OCT2 inhibitor against CP nephrotoxicity and its proficient role in attenuating oxidative stress, inflammatory status and apoptotic status.

A method for the long-term cultivation of mammalian cells in the absence of oxygen: Characterization of cell replication, hypoxia-inducible factor expression and reactive oxygen species production.

The center of tumors, stem cell niches and mucosal surfaces all represent areas of the body that are reported to be anoxic. However, long-term study of anoxic cell physiology is hindered by the lack of a sustainable method permitting cell cultivation in the complete absence of oxygen. A novel methodology was developed that enabled anoxic cell cultivation (17d maximum time tested) and cell passage. In the absence of oxygen, cell morphology is significantly altered. All cells tested exhibited morphologic changes, i.e., a combination of tethered (monolayer-like) and runagate (suspension-like) morphologies. Both morphologies replicated (Vero and HeLa cells tested) and could be passaged anaerobically. In the absence of exogenous oxygen, anoxic cells produced reactive oxygen species (ROS). Anaerobic runagate HeLa and Vero cells increased ROS production from day 3 to day 10 by 2- and 3-fold, respectively. In contrast, anoxic tethered HeLa and Vero cells either showed no significant change in ROS production between days 3 and 10 or exhibited a 3-fold decrease in ROS, respectively. Detection of ROS was inversely related to detection of hypoxia-inducible factor-1α (HIF1) mRNA and HIF-1 protein expression which cycled over a 10-day period. This methodology has broad applications for the study of tumor and stem cell physiology as well as gastrointestinal cell-microbiome interactions. In addition, sustainable anaerobic cell culture may lead to the identification of novel pathways and targets for chemotherapeutic drug development.