Zn O nanoparticles toxicity studied on isolated heart

Zn. O nanoparticles toxicity studied on isolated heart model Tamara Milivojević, Ph. D University of Ljubljana, Biotechnical faculty, Department of Biology

Zn. O NPs

Experimental approach 6 weeks oral exposure to: 4. 76 -47. 60 mg Zn. O NPs/kg b. w. /day Left ventricle developed pressure Coronary flow Heart rate Durration of arrhythmia Lactate dehydrogenase activity

Zn. O NPs chronic effect on wistar rat coronary parameters Zn. O NPs effect on left ventrical developed pressure (LVDP): § 47. 6 mg Zn. O/kg bw/day had more pronounced effect on LVDP, with maximum decrease in values up to 3. 3 -fold § 4. 76 mg Zn. O/kg bw/day lowered LVDP values up to 2. 0 fold Zn. O NPs effect on coronary flow: § 47. 6 mg Zn. O/kg bw/day had more pronounced effect on coronary flow even before ischemic period § 4. 76 mg Zn. O/kg bw/day effected the coronary flow within the first 15 min of reperfusion

Zn. O NPs chronic effect on wistar rat coronary parameters experimental groups control monitored parameters Zn. O NPs effect on heart rate: • No observed effect 4. 76 mg Zn. O NPs/kg of body weight/day 47. 60 mg Zn. O NPs/kg of body weight/day the duration of arrhythmia (s), means ± SE asystole 267 ± 5 149 ± 9 265 ± 8. 6 ventricular fibrillation 114 ± 25 76 ± 0 132 ± 17 ventricular tachycardia 5± 0 847 ± 110 (**) 99. 5 ± 22. 8 (**) extrasysole 121 ± 11. 7 135 ± 15 90 ± 9 Zn. O NPs effect on the duration of arrhythmia: • Both treatments induced increase in ventricular tachycardia

Enzyme activity analysis Zn. O NPs effect on lactate dehydrogenase (LDH) release: • Similar significant decrease in LDH release in both treatments, maximum decrease in values up to 2. 5 -fold

Conclusions § Chronic 6 weeks dietary exposure to Zn. O NPs induced specific and measurable compensatory response, which manifested uppermost in higher dose (47. 6 mg Zn. O/kg bw/day) as a decrease in left ventrical developed pressure and coronary flow. § the presence of arrhythmia suggests that chronic ingestion of doses lower than previously reported no-observed-adverse-effect-level NOAEL for mammals (Chung et al. , 2013): • 500 mg Zn. O NPs/kg single dose • 125 mg Zn. O NPs/kg b. w. /day 90 days exp can induce arrhythmogenic changes after chronic ingestion § Taken our results together, we suggest caution in the use of products containing Zn. O NPs.

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