Species- and sex-specific renal cytotoxicity of Ochratoxin A and B in vitro

Four different cell models were chosen for comparison of OTA and OTB toxici ty: primary porcine (PKC), rat (RPTC) and human renal proximal epithelial c ells (HKC) from both sexes and a porcine renal cell line: LLC-PK1. Culture conditions were tested and optimized for each respective cell type (species /sex and origin). All cell types were characterized for epithelial origin a nd growth patterns and following optimization of dosing strategies and assa y procedures, a strict study design was implemented to avoid systemic varia tions. Due to possible sensitivity differences, three simple endpoints were chosen to provide basic data for interspecies comparison: neutral red upta ke, MTT reduction and cell number. Of the endpoints tested neutral red appe ared the most sensitive, although all three parameters yielded comparable E C50's. Sex-differences were observed between male and female HKC cells foll owing 96 h exposure to OTA, with HKC(m) being more sensitive than HKC(f). N o sex-difference was observed in PKC cells, however, the PKC were approxima tely 3 and 10 times more sensitive than HKC(m) and HKC(f), respectively, to OTA and OTB. Interestingly, the CI95 of the Ec(50) values obtained for OTA (15.5-16.5 muM) and OTB (17.0-21.0 muM) were comparable in the PKC cells, in contrast, OTB had lower cytotoxicity than OTA in HKC and LLC-PK1 (approx . 2-fold) and no effects in RPTC. Overall. HKC(m) were nearly as sensitive as PKC towards OTA, followed by RPTC, LLC-PK1 and HKC(f), thus suggesting a sex specific sensitivity in humans towards OTA induced cytotoxicity.