title: In vitro toxicology assessment of cadmium bioavailability on primary porcine oviductal epithelial cells.
abstract: This study assessed the in vitro effects of cadmium ion (Cd(2+)) and cadmium-fulvic acid complexes (Cd(2+)-FA) on porcine oviductal epithelial cells (POEC) using transmission electron microscopy (TEM). Fresh POEC were cultured for 24h and then exposed for 3h in the tested solutions. Absorbed cadmium was analyzed by graphite furnace atomic absorption spectrophotometer (AAS). Dissociation and exchange rate constants were determined using the competing ligand, Chelex-100 and predicted cadmium species were calculated using the MINTEQA2 program. The results showed that the dissociation rate constant of Cd(2+)-FA was equal to 1.023×10(-3)s(-1) which was slower than the exchange rate at 2.062×10(-3)s(-1). Nevertheless, the absorbed concentrations of Cd(2+) and Cd(2+)-FA of POEC were similar and were 47±6.25μgL(-1) and 54±3.61μgL(-1), respectively. Although both levels of absorptions were not significantly different (t-test p=0.168 at α 0.01), their morphological effects as examined by TEM were substantially different with the effects being most marked with Cd(2+)>Cd(2+)-FA>FA. Aggregations around nuclei and nuclear membranes were observed with FA treatment whilst Cd(2+)-FA treatment produced more cytoplasmic damage. Cd(2+) treatment caused nuclear deformities. In conclusion, FA appears to penetrate the cells but was less likely to enter the nucleus. It also reduced the toxicity of Cd(2+) as the nuclei from the Cd(2+)-FA treatment appeared normal. Nevertheless, some Cd(2+) could still enter the nucleus. This might be because there was still 67.8% Cd(2+) left unbound from the Cd(2+)-FA treatment as calculated from the MINTEQA2 program compared to 99.1% Cd(2+) with Cd(2+) treatment, thus underlining the inherent toxicity of soluble cadmium ion.
authors.affiliation: Department of Environmental Science, Faculty of Science, Silpakorn University, Nakorn Pathom 73000, Thailand.
authors.forename: Natdhera
authors.initials: N
authors.lastname: Sanmanee
authors.forename: Mayuva
authors.initials: M
authors.lastname: Areekijseree