**4. Conclusions**

DNA adduct 8-Hydroxy-2'-Deoxyguanosine (8-OHdG) on urine sample of rats as a biomarker of DNA damage from BPA compounds and Ni (II) metals exposure, was formed and achieved the detection limit value. Levels of DNA adduct 8-OHdG in Sprague–Dawley rats after BPA/BPA and Ni (II) exposure was higher than levels of 8-OHdG in Sprague–Dawley control rats. It was also found that there was an increase in levels of DNA adduct 8-OHdG in Sprague–Dawley rats exposed to BPA and BPA-Ni (II) metals from first week exposure time until fourth week of exposure time (28 days). However, levels of 8-OHdG in rats exposed by BPA-Ni (II) is less than levels of 8-OHdG in rats exposed by BPA only. It can caused by the doses of BPA-Ni (II) metals administered to rats were in a non-excessive state, therefore the synergic effect of two toxic substances in the formation of 8-OHdG has not already been seen. There is possibility of the role of o-Quinones in metabolic cycle of BPA administered the increases of hydroxyl radical levels. And the role of Fenton-like reaction might give synergistic effect in the formation of hydroxyl radicals at the excessive level of Ni(II).

### **Acknowledgements**

The authors would like to thank Universitas Indonesia for funding this research through PITTA Grant Universitas Indonesia 2018 with contract number 2242/UN2. R3.1/HKP.05.00/2018.

*In Vivo Study of DNA Adduct (8-OHdG) Formation of* Rattus novergicus *Using Bisphenol… DOI: http://dx.doi.org/10.5772/intechopen.99432*
