Toxicity and risk assessment of mercury exposures from cinnabar and Baizi Yangxin Pills based on pharmacokinetic and tissue distribution studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Baizi Yangxin Pills (BZYXP), a popular cinnabar (α-HgS) contained Traditional Chinese Medicines (TCMs) is widely used in clinical trials. However, mercury is one of the most toxic elements. The adverse effects of cinnabar-containing TCMs have been occasionally reported in recent years, leading to the growing concerns about their toxicity and safety. AIM OF THE STUDY: The health risks of BZYXP and cinnabar related to the mercury exposures were evaluated through blood pharmacokinetic and tissue distribution studies in rats. MATERIALS AND METHODS: The distribution of absorbed mercury in rats' blood and tissues were measured by the developed cold-vapor atomic fluorescence spectrometric method. And the tissue damages were determined through the histopathological examinations. For single dose study, the low and high oral doses were equivalent to 1 and 10-fold therapeutic dose, respectively. The multiple doses study was conducted at low and high dose levels every 12 h for 30 consecutive days. RESULTS: Significant differences of mercury blood pharmacokinetic and tissue distribution characteristics were observed between the corresponding BZYXP and cinnabar groups. The herbal ingredients in BZYXP promoted the absorption of bio-accessible mercury of cinnabar and prolonged the elimination process, posing potential health risks. Although mercury was found easily accumulated in kidney, liver and brain tissues, kidney and liver didn't show obvious damages even after 30 days consecutive administration of BZYXP or cinnabar at 10-fold clinically equivalent doses. But brain did show some histopathological changes, and autonomic activities of rats decreased, pointing the potential neurotoxicity. CONCLUSIONS: Mercury tend to be accumulated especially when over-dose or prolonged medication with cinnabar-containing TCMs are given. The mercury exposures even at therapeutic doses of BZYXP or cinnabar do pose health risks from the neurotoxicity point of view.

Evaluation of hepatotoxicity potential of a potent traditional Tibetan medicine Zuotai.

ETHNOPHARMACOLOGICAL RELEVANCE: Zuotai (gTso thal) has a long history in the treatment of cardiovascular disease, liver and bile diseases, spleen and stomach diseases as a precious adjuvant in Tibetan medicine. However, Zuotai is a mercury preparation that contains 54.5% HgS. Its application has always been controversial. AIM OF THE STUDY: To evaluate the toxicological effects of Zuotai in hepatocytes and in zebrafish. MATERIALS AND METHODS: MTT was used to determine the survival rate of hepatocytes; Hoechst and TUNEL staining were used to detect the apoptosis cells; Western blot and RT-qPCR assay were used to determine the expression levels of the protein and mRNA; Liver morphology observation and H&E staining were used to evaluate the hepatotoxicity of Zuotai in Zebfrafish. RESULTS: The survival rate of L-02 cells, HepG2 cells and RBL-2A cells reduced by Zuotai (10-4-0.1 mg/mL) in a dose and time-dependent manner. Zuotai (0.1 mg/mL) induced HepG2 cells shrinkage, condensation and fragmentation and increased the number of apoptosis cells. The protein expression levels of cleaved Caspase-3 and Bax were increased and the expression levels of Bcl-2 were reduced after HepG2 cells exposed to Zuotai (10-4-0.1 mg/mL) for 24 h. In addition, Zuotai (0.2 mg/mL) induced the darker liver color of the larval zebrafish and changed the liver morphologic of adult zebrafish. Zuotai (0.2 mg/mL) also increased the mRNA levels of CYP1A1, CYP1B1 and MT-1 in the liver of adult zebrafish. However, no significantly hepatotoxicity was observed after hepatocytes and zebrafish exposed to HgS at the same dose. CONCLUSIONS: Results showed that Zuotai induced hepatotoxicity effectively under a certain dose but its hepatotoxicity likely occurs via other mechanisms that did not depend on HgS.

A review of cinnabar (HgS) and/or realgar (As4S4)-containing traditional medicines.

ETHNOPHARMOCOLOGICAL RELEVANCE: Herbo-metallic preparations have a long history in the treatment of diseases, and are still used today for refractory diseases, as adjuncts to standard therapy, or for economic reasons in developing countries. AIM OF THE REVIEW: This review uses cinnabar (HgS) and realgar (As4S4) as mineral examples to discuss their occurrence, therapeutic use, pharmacology, toxicity in traditional medicine mixtures, and research perspectives. MATERIALS AND METHODS: A literature search on cinnabar and realgar from PubMed, Chinese pharmacopeia, Google and other sources was carried out. Traditional medicines containing both cinnabar and realgar (An-Gong-Niu-Huang Wan, Hua-Feng-Dan); mainly cinnabar (Zhu-Sha-An-Shen Wan; Zuotai and Dangzuo), and mainly realgar (Huang-Dai Pian; Liu-Shen Wan; Niu-Huang-Jie-Du) are discussed. RESULTS: Both cinnabar and realgar used in traditional medicines are subjected to special preparation procedures to remove impurities. Metals in these traditional medicines are in the sulfide forms which are different from environmental mercurials (HgCl2, MeHg) or arsenicals (NaAsO2, NaH2AsO4). Cinnabar and/or realgar are seldom used alone, but rather as mixtures with herbs and/or animal products in traditional medicines. Advanced technologies are now used to characterize these preparations. The bioaccessibility, absorption, distribution, metabolism and elimination of these herbo-metallic preparations are different from environmental metals. The rationale of including metals in traditional remedies and their interactions with drugs need to be justified. At higher therapeutic doses, balance of the benefits and risks is critical. Surveillance of patients using these herbo-metallic preparations is desired. CONCLUSION: Chemical forms of mercury and arsenic are a major determinant of their disposition, efficacy and toxicity, and the use of total Hg and As alone for risk assessment of metals in traditional medicines is insufficient.

[Pharmacokinetics of mercury after oral administration of cinnabaris and Fufang Niuhuang Xiaoyan capsule in rats].

Fufang Niuhuang Xiaoyan capsule was a classical compound prescription with the efficacy of heat-clearing, detoxification, sedation and anti-inflammation, with cinnabaris as one of its active ingredients. The study focuses on the pharmacokinetics of mercury in rats after oral administration of cinnabaris and Fufang Niuhuang Xiaoyan capsule, in order to explore the effect of combined traditional Chinese medicines on mercury metabolism. In this study, the method of nitric-perchloric acid digestion system coupled with cold atomic-atomic fluorescence spectroscopy (CV-AFS) was adopted to accurately determine mercury in whole blood of rats. Fufang Niuhueng Xiaoyan capsule had three dose schemes of oral administration, namely equivalent clinical dose, 3 times of equivalent clinical dose and 10 times of equivalent clinical dose; And the doses of oral administration of cinnabaris was calculated according to that of Fufang Niuhuang Xiaoyan capsule. SPF grade healthy SD rats were fasted overnight before the oral administration with cinnabaris suspension (or Fufang Niuhuang Xiaoyan capsule suspension). After oral administration of different doses of cinnabaris, no obvious changes in tmax and MRT were observed, while Cmax/dose, AUC0-48 h/dose and AUC0-∞/dose decreased with the increase in dose, indicating that total mercury absorption in body was declining. As the dose increased, Ke, CL/F decreased, and t1/2 increased, indicating that the elimination slowed down, and mercury metabolism showed non-linear dynamic characteristics within a certain range of dose (22-220 mg•kg⁻¹). The total mercury metabolism in the whole blood of rats after oral administration with different doses of Fufang Niuhuang Xiaoyan capsule also showed non-linear dynamic characteristics. The results were correlated with the low solubility of cinnabaris in the body. Compared with cinnabaris, Fufang Niuhuang Xiaoyan capsule showed no obvious changes in V/F and MRT, while Ke, CL/F, tmax decreased, and t1/2, Cmax/dose, AUC0-48 h/dose, AUC0-∞/dose increased significantly. The results showed that Fufang Niuhuang Xiaoyan capsule accelerated absorption, slowed down elimination and improved the total absorption of mercury in the whole blood, indicating that Fufang Niuhuang Xiaoyan capsule may contain components for promoting absorption and alleviating elimination of mercury. Fufang Niuhuang Xiaoyan capsule had an impact on the pharmacokinetics of cinnabaris, and long-term administration of cinnabaris (Fufang Niuhuang Xiaoyan capsule) was possible to cause accumulation of mercury in the body. This study could explain changes in efficacy of Fufang Niuhuang Xiaoyan capsule, evaluate the rationality of compound medicines containing toxic elements and provide scientific basis for the rational and safe use of Fufang Niuhuang Xiaoyan capsule.

Zuotai and HgS differ from HgCl2 and methyl mercury in Hg accumulation and toxicity in weanling and aged rats.

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 (ß-HgS) are different from mercury chloride (HgCl2) 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 (21d) and aged (450d) rats were orally given Zuotai (54% ß-HgS, 30mg/kg), HgS (α-HgS, 30mg/kg), HgCl2 (34.6mg/kg), or MeHg (MeHgCl, 3.2mg/kg) for 7days. Accumulation of Hg in kidney and liver, and the toxicity-sensitive gene expressions were examined. Animal body weight gain was decreased by HgCl2 and to a lesser extent by MeHg, but unaltered after Zuotai and HgS. HgCl2 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 HgCl2 and MeHg, but unaffected by Zuotai and HgS. Thus, Zuotai and HgS differ from HgCl2 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.

Bioavailability study of arsenic and mercury in traditional Chinese medicines (TCM) using an animal model after a single dose exposure.

Traditional Chinese medicines (TCM) are increasingly being used as alternative medicines in many countries, and this has caused concern because of adverse health effects from toxic metal bioavailability such as mercury (Hg) and arsenic (As). The aim of this study was to investigate the bioavailability of As and Hg from TCM after a single exposure dose using an animal model of female Sprague-Dawley rats. The rats were divided into 6 groups which included four groups treated with sodium arsenite (NaAsO2), arsenic sulfide (As2S3), mercuric chloride (HgCl2), mercuric sulfide (HgS), and two groups treated with TCM containing high Hg or As (Liu Shen Wan: As 7.7-9.1% and Hg 1.4-5.0%; Niuhang Jie du Pian: As 6.2-7.9% and Hg <0.001%). The samples of urine, faeces, kidney and liver were collected for analysis and histological assay. The results indicated that relatively low levels of As and Hg from these TCM were retained in liver and kidney tissues. The levels of As in these tissues after TCM treatment were consistent with the levels from the As sulphide treated group. With the exception of the mercuric chloride treated group, the levels of Hg in urine from other groups were very low, and high levels of As and Hg from TCM were excreted in faeces. The study showed poor bioavailability of As and Hg from TCM as indicated by low relative bioavailability of As (0.60-1.10%) and Hg (<0.001%). Histopathological examination of rat kidney and liver tissues did not show toxic effects from TCM.

Minimal change disease caused by exposure to mercury-containing skin lightening cream: a report of 4 cases.

Mercury is a known cause of nephrotic syndrome and the underlying renal pathology in most of the reported cases was membranous nephropathy. We describe here 4 cases of minimal change disease following exposure to mercury-containing skin lightening cream for 2 - 6 months. The mercury content of the facial creams was very high (7,420 - 30,000 parts per million). All patients were female and presented with nephrotic syndrome and heavy proteinuria (8.35 - 20.69 g/d). The blood and urine mercury levels were 26 - 129 nmol/l and 316 - 2,521 nmol/d, respectively. Renal biopsy revealed minimal change disease (MCD) in all patients. The use of cosmetic cream was stopped and chelation therapy with D-penicillamine was given. Two patients were also given steroids. The time for blood mercury level to normalize was 1 - 7 months, whereas it took longer for urine mercury level to normalize (9 - 16 months). All patients had complete remission of proteinuria and the time to normalization of proteinuria was 1 - 9 months. Mercury-containing skin lightening cream is hazardous because skin absorption of mercury can cause minimal change disease. The public should be warned of the danger of using such products. In patients presenting with nephrotic syndrome, a detailed history should be taken, including the use of skin lightening cream. With regard to renal pathology, apart from membranous nephropathy, minimal change disease should be included as another pathological entity caused by mercury exposure or intoxication.

Effect of Ayurvedic mercury preparation Makaradhwaja on geriatric canine--a preliminary study.

Makaradhwaja, an alchemical Ayurvedic mercury preparation is used as stimulant and vitalizer. Towards veterinary practices, the acceptability, tolerability and toxicity studies were undertaken in geriatric pet dogs aged more than 10 years irrespective of breed and sex for future use. Makaradhwaja (2.5 mg/kg) was used with honey once daily for 30 days. Before and after treatment, blood was collected for hematological studies as well as liver, kidney function and anti-oxidant activity. In control group, honey itself showed no appreciable change whereas, Makaradhwaja lowered neutrophil and total leucocyte count. Serum cholesterol, urea, glucose, alanine amino transferase, aspartate amino transferase, sodium, phosphorus and calcium were decreased. Haemoglobin and serum creatinine were significantly increased. There was appreciable physical, behavioral and body weight change including quality of life. The dose was used in replication of human dose (125 mg/50 kg). Anti-oxidant study showed significant increase of lipid per oxidation in experimental group while the values of ABTS radical cation decolorisation assay although decreased but did not show any significant changes. Decrease of serum urea and increase of serum creatinine could not be explained on single dose response. Different dose study could only explain the optimum dose to be required in canine practices.

[Comparative toxicology study of Cinnabar, Zhusha Anshenwan, methylmercury and mercuric chloride].

OBJECTIVE: To study the toxicity of Cinnabar and Cinnabar-containing traditional medicines (Zhusha Anshenwan) comparable to common mercurials. METHOD: The toxicity of methylmercury (MeHg), mercuric chloride (HgCl2), Cinnabar and Zhusha Anshenwan was studied in cultured human liver HL-7702 cells and in mice following acute and subacute exposures. RESULT: The 50% lethal concentrations (LC50) of MeHg, HgCl2, Cinnabar and Zhusha Anshenwan in human liver HL-7702 cells were 4.4, 9.2, 2460, 4050 mg x L(-1), respectively . Oral cinnabar at a dose of 20 g x kg(-1) (clinical dosage 250 times) did not kill mouse, but no mouse could survive MeHg at a dose of 0.1 g x kg(-1) or HgCl2 at a dose of 0. 15 g x kg(-1). Subacute toxicity experiment indicated that HgCl2 retarded body weight gain with significant accumulation of Hg in the liver and kidney. In comparison, mercury accumulation after Cinnabar and Zhusha Anshenwan was insignificant. No apparent hepatic and renal dysfunctions were evident under the experimental conditions, but the metallothionein-2 mRNA levels were much higher in HgCl2 group than in other groups. CONCLUSION: Cinnabar and Zhusha Anshenwan are much less toxic than MeHg and HgCl2.

[Study on hepatoxicity and nephrotoxicity of cinnabar in rats].

OBJECTIVE: To investigate hepatoxicity and nephrotoxicity of cinnabar to provide the scientific basis for safe uses in clinic. METHOD: Maximally tolerated dose of cinnabar (MTD) was tested by single oral administration. Chronic toxicity of cinnabar at different dose level (0.025, 0.05, 0.1, 0.4, 0.8 g x kg(-1) x d(-1)) corresponding to 1/2, 1, 2, 8, 16 times of clinic doses of cinnabar was investigated. The rats were treated with the cinnabar through oral administration once a day for successive 90 days. Urinary qualitative test, blood routine examination, serum chemistry measurement and histomorphologic observation were conducted at day 30, 60 and 90. Toxic changes related to the treatment of cinnabar and no-observed adverse effect level (NOAEL) were evaluated. RESULT: For the content of 98.1% total Hg and 21.5 microg x g(-1) absoluble Hg, MTD of cinnabar with oral administration was 24 g x kg(-1) (corresponding to 516 microg x kg(-1) absoluble Hg), equivalent to 3,000 times of clinical daily dose for an adult, and no obvious adverse effect was showed at this dose. Cinnabar can cause kidney and liver pathological changes when it is repeatedly administrated for over 30 days. The kidney was more sensitive to cinnabar than liver. Based on repeated dose toxicity study, NOAELs were 0.1, 0.05 g x kg(-1) x d(-1)) respectively for 30 day and 90 day treatment, and those were approximately accumulative intake of absoluble Hg 64.5 microg x kg(-1) and 96.76 microg x kg(-1). Thus, for safe use of cinnabar, the acceptable daily intake (ADI) of cinnabar was 0.0009-0.0017 g x kg(-1) x d(-1), namely daily dose 0.05-0.1 g for an adult with body weight about 60 kg. Considering the difference of drug sensitivity and lifecircle between human and rats, we suggest that cinnabar which contains absoluble Hg < or = 21 microg x g(-1) should be used for no longer than 2 weeks at daily dose 0.05-0.1 g. CONCLUSION: Long term use of cinnabar can cause kidney and liver pathological change, so the dose and administration duration should be limited. The suggestion is as follows: cinnabar which contains absoluble Hg < or = 21 microg x g(-1) should be used less than 2 weeks at the daily dose below 0.05-0.1 g.

[Study of mercury cumulation in Cinnabar-treated rats].

OBJECTIVE: To investigate the mercury cumulation following single dose or long-term use of Cinnabar to rats. METHOD: The Cinnabar which was used in the study contains 98% insoluble mercuric sulfide (HgS) and 21.5 mg x kg(-1) soluble mercuric compounds. Two separate experiments were performed: (1) Tweenty-eight fasting SD rats were orally given a single dose of Cinnabar at the dose of 0.8 g x kg(-1) and the other four rats were given ultra-filtrated water served as control group. Blood, livers, kidneys and brains of four rats were taken out at 0.5, 1, 2, 4, 8, 16, 36 h respectively after treatment. Mercury quantity of each organ or blood sample was measured. (2) Forty SD rats were randomly divided into four groups: control group and Cinnabar 0.1, 0.4, 0.8 g x kg(-1) groups, each group containing 5 females and 5 males. The rats were intra-gastrically treated with Cinnabar once a day for successively 90 days, while the control group was given ultra-filtrated water. Mercury contents in blood, livers, kidneys and brain of each rat were measured at 16 h of fasting after last dosing. RESULT: Mercury contents of blood, liver, kidney and brain increased slightly after single dosing of Cinnabar at dose of 0.8 g x kg(-1), with the order from high to low liver > blood > brain > kidney. Whereas 90-day oral treatment of Cinnabar led to significant cumulation of mercury in organs but not in blood. Kidney' s cumulation of mercury was much higher than any other tested organs and blood. Brain's mercury cumulation was also very high. The contents of mercury in kidney and brain of 0.8 g x kg(-1) group (total intake of soluble mercury within 90 days was 1 548 microg x kg(-1)) were respectively 71.2 and 27.4 times higher than control group. Even though in the lowest dose 0.1 g x kg(-1) group (total intake of soluble mercury 194 microg? kg(-1)), the mercury cumulation folds in kidney and brain were 16.77 and 20.43 respectively. However, liver got lower mercury cumulation than kidney and brain, which led to only 2 folds mercury cumulation at dose of 0.8 g x kg(-1). Our previous study showed that 90-day administration of Cinnabar at the dose > or = 0.1 g x kg(-1) (total intake of soluble mercury 194 microg x kg(-1)) could cause pathological changes in kidney and liver, indicating both were the toxicity targets for Cinnabar. Those manifested that liver could be more sensitive than kidney to mercury. Though brain got 20 times mercury cumulation after 90 day treatment, the animals showed no abnormal signs in general behavior and brain histomorphology,which indicated that rat brain was not sensitive to mercury. CONCLUSION: Soluble mercury in Cinnabar can be absorbed causing high cumulated in some organs, such as kidney and brain after long-term use of Cinnabar. Liver had also mercury cumulation, but was much lower than kidney. Total intake of soluble mercury for > or = 194 microg x kg(-1) within 90 days could cause toxicosis by mercury cumulation.

[Monitoring early toxicity of heavy metals including Hg using a HSE-SEAP reporter gene].

OBJECTIVE: To develop a cellular assay based on heat shock signal pathway and secreted alkaline phosphatase (SEAP) reporter gene for investigating/predicting the early toxicity of heavy metals on HeLa cells in Chinese traditional medicine (TCM). METHOD: The pHSE-SEAP plasmid was transfected into HeLa cells to build a HSE-SEAP-HeLa cell model. For validation of the model, the transfected cells were treated by either heating at 42 degrees C for 1 h or incubated with 5 mol x L(-1) CdCl2 for 4 h. Then the cells were covered in complete DMEM culture medium for 48 h and the activity of SEAP (reflecting the cellular level of heat shock protein) in cultural supernatants was measured; meanwhile, cell viability was determined by MTT assays. In addition, the cells were treated by four mercury compounds, HgCl2, merthilate sodium, HgS and cinnabar at the sub-lethal concentrations (determined by MTT assays). Then the heat shock response was detected likewise. RESULT: Significant level of secreted alkaline phosphatase (SEAP) was found in pHSE-SEAP transfected HeLa cells treated either by heating (42 degrees C) or incubating with CdCl2. The heat shock protein was induced by CdCl2 before decrease of cell viability was observed. All four mercury compounds induced heat shock response in both time and concentration-dependant manner. However, there were big differences among the mercury compounds, suggesting potential differences for early-stage toxicity in vivo. CONCLUSION: The pHSE-SEAP transfected HeLa cells respond effectively to heat shock and metal stresses, and therefore provide a practical and repeatable assay for investigating/predicting the early toxicity of heavy metals and mineral-containing drugs in TCM.

Neurotoxic mechanism of cinnabar and mercuric sulfide on the vestibulo-ocular reflex system of guinea pigs.

Cinnabar, a naturally occurring mercuric sulfide (HgS), has been combined with Chinese herbal medicine as a sedative for more than 2000 years. To date, its neurotoxic effect on the vestibulo-ocular reflex (VOR) system has not been reported. By means of a caloric test coupled with electronystagmographic recordings, the effect of commercial HgS and cinnabar on the VOR system of guinea pigs was studied. HgS or cinnabar was administered orally (1.0 g/kg) to Hartley-strain guinea pigs once daily for 7 consecutive days. A battery of electrophysiological, biochemical, and histopathological examinations were performed. The results showed that HgS induced a 60% caloric response abnormality (40% caloric hyperfunction and 20% hypofunction), whereas the abnormal responses appeared to be more severe (six out of six) in the cinnabar group. The Hg contents of whole blood and cerebellum were increased and correlated to their neurotoxic effects on the VOR system, indicating that both insoluble HgS and cinnabar could be absorbed from the gastrointestinal tract and distributed to the cerebellum. Although the vestibular labyrinth revealed no remarkable change under light microscopy, loss of Purkinje cells in the cerebellum was detected, and the enzymatic Na(+)/K(+)-ATPase activity of cerebellum (a higher inhibitory center of the VOR system) was significantly inhibited by HgS and cinnabar. Moreover, cerebellar nitric oxide (NO) production was increased significantly. Hence, we tentatively conclude that the increased Hg contents in the cerebellum following oral administration of HgS and cinnabar were responsible, at least in part, for the detrimental neurotoxic effect on the VOR system. Potentially, decreasing Na(+)/K(+)-ATPase activity and increasing NO production within the cerebellar regulatory center are postulated to mediate this VOR dysfunction caused by the mercurial compounds and cinnabar.