ABSTRACT
Apoptosis induced by magnetic field in female rats was investigated by using the Tdtmediated dUTP nick-end labeling [TUNEL] assay in thymus, liver and kidney. Design: Female.s rats were exposure to 128 mT 1hour/day for 10 consecutive days. Small pieces of thymus, liver and kidney were fixed overnight at room temperature by direct immersion in 4% paraformaldehyde in 0.1M phosphate buffer, pH 7.4. The samples were dehydrated with ethanol and toluene and embedded in paraffin wax. Serial sections [5 microm thick] were mounted on gelatin-coated glass slides and stained with hematoxylin and eosin or treated with TUNEL [TdT-mediated dUTP-digoxigenin Nick and Labeling] method. Setting: Female Wistar rats were housed in a cage, with free access to food and water [Faculté des Sciences de Bizerte, Tunisia]. Rats were cared for under the Tunisian Code of Practice for the Care and Use of Animals for Scientific purpose and the Experimental Protocols were approved by the Ethics Committee. Subjects: Treated and control groups [n=12] weighing 100-150g at the time of experiments were housed in the same condition three weeks before the beginning of the experiments. Main outcome measures: MF-induced apoptosis in thymus was demonstrated by the terminal deoxynucleotidyl transferase [TdT] mediated dUTP-Biotin Nick End Labeling [TUNEL] assay. Results: Following sub-acute exposure to MF, morphological examinations revealed numerous apoptotic cells in thymus characterized by nuclear fragmentation and condensation [figure 2a]. Interestingly, no labeling was found in control thymus. The density of the apoptotic cells was significant in cortical zone compared to control [2.95 +/- 0.34% vs 0.74 +/- 0.10%, p<0.05], than in the medullar zone [2.105 +/- 0.356% vs 0.634 +/- 0.038%, p<0.05] [figure 2a, b]. By contrast, as shown in figures [3c, d], no labeling was found in liver and kidney following MF exposure [figure 4e, f]. Conclusions: Thus, it may be concluded that static magnetic field induced apoptosis in thymic cell death but not in the liver and kidney
ABSTRACT
To investigate the bio-effects of MF exposure on synthesis of plasma corticosterone and liver metallothionein [MT] concentrations in female rats Design: Female rats were exposed to 128 mT 1 hour/day for 10 consecutive days. Trunk blood of decapitated rats was collected and used for determination of corticosterone concentration. Quantification of MT was performed by using 109Cd. Whole liver were homogenized in 1 ml of a 0.25 M sucrose solution. Surgical Adrenalectomy [ADX] and sham-ADX were performed via dorsal approach under ether anesthesia. Setting: Female Wistar rats were housed in a cage, with free access to food and water [Faculte des Sciences de Bizerte, Tunisia]. Rats were cared for under the Tunisian Code of Practice for the Care and Use of Animals for Scientific purpose and the Experimental Protocols were approved by the Ethics Committee. Subjects: Treated and control groups [n=12] weighing 100-150g at the time of experiments were housed in the same condition three weeks before the beginning of the experiments. Main outcome measures: Counting radioactivity will be used as analysis marker of bio-effects of magnetic field. Sub-Acute exposure to magnetic field the exposition of rats 1 hour/day for 10 consecutive days to MF of 128 mT induced a significant increase [+104%, p<0.05] of plasma corticosterone concentrations showing a stress-state. Interestingly, MF induced an increase of metallothionein levels [+122%, p<0.05] in liver compared to controls. By contrast, levels of MT in adrenalectomised rats remained unchanged following MF exposure. Conclusions: The results presented above show, for the first time, that sub-acute exposure to MF stimulates plasma corticosterone and MT activities in female rats. Indeed, we have noted an apparent lack of MT response to MF exposure in adrenalectomized rats, indicating that probably biosynthesis of MT was induced by stress