engleski

Expression of hsp70 in LLC-PK1 and MDCK cells exposed to ochratoxin A

Introduction: Ochratoxin A (OTA) is a possible etiological agent of endemic nephropathy, a chronic renal disease with high prevalence in limited geographic areas. Ochratoxicosis has many characteristics of different pathological states in which heat shock proteins (Hsps) are usually induced. The most inducible heat shock proteins belong to the Hsp70 family. Material and Methods: Hsp70 was determined by the Western blot in kidneys of rats chronically treated with a low dose of OTA and in LLC-PK1 and MDCK cells exposed to OTA. Estimation of cell viability and release of lactate dehydrogenase (LDH) confirmed the toxic effects of OTA on cultured cells. Results: OTA affects quantitative distribution between two Hsp70s isoforms (68kDa- and 74kDa- isoforms) but does not induce Hsp70 in rat kidney. No changes in the Hsp70 level were detected in LLC-PK1 and MDCK cells treated with OTA, although the cells were seriously injured, as seen from the reduced cell viability and increased release of LDH. Both cell lines were capable of inducing Hsp70 following a heat shock. However, exposure of the cells to OTA before the heat shock challenge prevented Hsp70 induction. Conclusion: Results of the presented study show that OTA does not induce Hsp70 in rat kidney and in cultured kidney cells. The absence of Hsp70 protective effects in the cells and tissues might be a possible explanation for the cumulative destructive effects of OTA and a silent onset of endemic nephropathy in humans and OTA-induced experimental nephrotoxicity in animals.

ochratoxin A; hsp70; LLCPK-1; MDCK

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