Zuotai and HgS differ from HgCl{sub 2} and methyl mercury in Hg accumulation and toxicity in weanling and aged rats

• Published in: Toxicology and applied pharmacology Vol. 331
• Main Authors: Zhang, Bin-Bin, Li, Wen-Kai, Hou, Wei-Yu, Luo, Ya, Shi, Jing-Zhen, Li, Cen, Wei, Li-Xin, Liu, Jie
• Format: Journal Article
• Language: English
• Published: United States 15.09.2017
• Subjects: 60 APPLIED LIFE SCIENCES; ANIMAL TISSUES; DRUGS; ELDERLY PEOPLE; GENES; KIDNEYS; LIVER; MEDICINE; MERCURY CHLORIDES; METHYLMERCURY; PLANT TISSUES; RATS; TOXICITY
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/J.TAAP.2017.05.021

Mercury sulfides are used in Ayurvedic medicines, Tibetan medicines, and Chinese medicines for thousands of years and are still used today. Cinnabar (α-HgS) and metacinnabar (β-HgS) are different from mercury chloride (HgCl{sub 2}) and methylmercury (MeHg) in their disposition and toxicity. Whether such scenario applies to weanling and aged animals is not known. To address this question, weanling (21 d) and aged (450 d) rats were orally given Zuotai (54% β-HgS, 30 mg/kg), HgS (α-HgS, 30 mg/kg), HgCl{sub 2} (34.6 mg/kg), or MeHg (MeHgCl, 3.2 mg/kg) for 7 days. Accumulation of Hg in kidney and liver, and the toxicity-sensitive gene expressions were examined. Animal body weight gain was decreased by HgCl{sub 2} and to a lesser extent by MeHg, but unaltered after Zuotai and HgS. HgCl{sub 2} and MeHg produced dramatic tissue Hg accumulation, increased kidney (kim-1 and Ngal) and liver (Ho-1) injury-sensitive gene expressions, but such changes are absent or mild after Zuotai and HgS. Aged rats were more susceptible than weanling rats to Hg toxicity. To examine roles of transporters in Hg accumulation, transporter gene expressions were examined. The expression of renal uptake transporters Oat1, Oct2, and Oatp4c1 and hepatic Oatp2 was decreased, while the expression of renal efflux transporter Mrp2, Mrp4 and Mdr1b was increased following HgCl{sub 2} and MeHg, but unaffected by Zuotai and HgS. Thus, Zuotai and HgS differ from HgCl{sub 2} and MeHg in producing tissue Hg accumulation and toxicity, and aged rats are more susceptible than weanling rats. Transporter expression could be adaptive means to reduce tissue Hg burden. - Highlights: • Aged rats are more susceptible to HgCl{sub 2} and MeHg toxicity than weanling rats. • Zuotai and HgS differ from HgCl{sub 2} and MeHg in producing toxicity. • Zuotai and HgS differ from HgCl{sub 2} and MeHg in much less tissue Hg accumulation. • Renal transporters are altered by HgCl{sub 2} and MeHg, but unaffected by Zuotai and HgS • Liver transporters are less affected than kidney transporters by HgCl{sub 2} and MeHg.