Detection of DNA Fragmentation in Liver of Goats Exposed to Lead Poisoning in Bagega District of Zamfara State, Nigeria

Summary: The ubiquitous presence of lead (Pb) and its release by anthropogenic activities has remained a major environmental pollution risk to both humans and animals. Lead toxicity has been associated with different systemic toxicities and biochemical impacts (such as oxidative stress and DNA damaging effects) with dire health consequences. In Nigeria, the health problem associated with lead toxicity has been overwhelming in the Bagega District of Zamfara State where artisanal gold mining has resulted in widespread environmental lead contamination. For this study, 24 goats were selected from two communities, 12 goats (exposed groups) selected from Bagega District, Zamfara (a community with widespread mining and lead contamination), while 12 goats (control) were selected from Apete, Ibadan with no previous mining history. The liver lead levels in the two groups were evaluated using the using Atomic Absorption Spectrophotometry and the lead level in the exposed group was categorized into 3 exposure categories (viz mild, moderate and severe). Representative liver samples from the 3 tissue lead exposure categories were analyzed using agarose gel electrophoresis for the detection of apoptotic oligonucleosomal DNA fragmentation. The tissue lead level in the goats from the exposed group (32.42±13.85 mg/kg) was significantly higher than the control group (0.36±0.12 mg/kg). DNA ladder was detected in the 3 exposure categories with a dose-related degree of DNA fragmentation. This study highlights the role of oligonucleosomal DNA fragmentation and apoptosis in the pathogenicity of lead in lead exposed goats and the associated the dose-gradient impact of tissue lead level on the degree of DNA fragmentation.