Preparation and anti-inflammatory effect of mercury sulphide nanoparticle-loaded hydrogels.

We successfully prepared mercury sulphide nanoparticle hydrogels by physical encapsulation method. The successfully prepared mercuric sulphide nanoparticle hydrogel was a zinc folate hydrogel, which showed an obvious porous structure with interconnected and uniformly distributed pores and a pore size range of about 20 µm. The maximum drug loading of the hydrogels was 3%, and the in vitro cumulative release degree was in accordance with the first-order kinetic equation Mt = 149.529 (1 - e-0.026t). The particles in mercuric sulphide nanoparticle hydrogels significantly down-regulated the expression of the cell surface co-stimulatory molecule CD86 (p < .0001). Meanwhile, the inflammatory response was regulated through the NF-κB pathway in LPS-induced inflammatory cells. Later, it was observed that mercuric sulphide nanoparticle hydrogels could significantly counteract the inflammatory and immune models through a mouse ear swelling model, a rat foot-plantar swelling model and a rheumatoid arthritis model. This design targets the immunomodulatory, and anti-inflammatory effects through nanocomposite hydrogel technology. It reduces the drawbacks of low mercury utilisation and susceptibility to accumulation of toxicity. It aims to provide an experimental basis for the development of mercuric sulphide and the treatment of inflammatory and immune-related diseases.HighlightsMercury sulphide nanoparticle hydrogel has an optimal mercury sulphide nanoparticle content of 2%, is structurally homogeneous and stable, and does not exhibit significant liver or kidney toxicity.Mercuric sulphide nanoparticle hydrogel exerts anti-inflammatory effects in cells and rats, and regulates the expression of macrophage surface molecules and factors related to the NF-κB pathway.Mercuric sulphide nanoparticle hydrogel improves the condition of ankle synovial joints in a rat model of rheumatoid arthritis.

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.

Early developmental exposure to inorganic mercury does not alter affiliative behavior of adult prairie voles (Microtus ochrogaster).

Mercury chloride exposure through drinking water in adult male prairie voles (Microtus ochrogaster) has been shown to alter their social behavior. Here, we examined the potential disruption of adult social behavior in prairie voles that were exposed to 60 ppm mercury during early development. We used a cross-fostering approach to test the effects of mercury exposure: (1) from conception until birth; (ii) from birth until weaning; and (iii) from conception until weaning, on adult affiliative behavior. Untreated and mercury-treated voles were given the option of remaining in an empty cage or affiliating with a same-sex conspecific in a 3-h choice test. We found that early developmental mercury exposure had little if any effect on the reproductive success of breeder pairs or on affiliative behavior by either sex when subjects were tested as adults. These results suggest that, at least in the context of the behavior tested, the effects of early developmental exposure to mercury do not permanently alter adult prairie vole affiliative behavior, or do so in a way that is too subtle to be detected using the current testing paradigm.

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.

Effect of mercury vapor inhalation on rat ovary: Stereology and histopathology.

AIM: Mercury, an environmental contaminant, is a risk factor for health in whole living organisms. In this study, we investigated whether mercury vapor (HgO) inhalation has an effect on rat ovary. METHODS: Twelve Wistar albino rats were divided equally into experimental (Hg) and control groups (n = 6). Animals in the Hg group were exposed to HgO for 45 days at a dose 1 mg/m(3)/day, after which, histological and stereological assessment were carried out. RESULTS: Ovaries exposed to HgO had histo-morphometric alterations. HgO inhalation resulted in reduction of the total number of primordial, primary and Graaf follicles. Also, mean volume of ovary, medulla and cortex, corpus luteum (c. luteum) and Graaf follicles was decreased in the Hg group. Moreover, there was a significant increase in total volume of the atretic follicles. On light microscopy, thickening of tunica albuginea, increase of fibrils within the connective tissue, congestion of the capillaries and venous vessels, thinned walls and fibrin deposition in some large blood vessels, and edema were seen. Also, irregular follicle and oocyte borders, and hydropic degeneration in follicular granulosa cells were detected. CONCLUSION: Structural alterations could be attributed to the toxic influence of HgO on rat ovary. The use of Hg should therefore be more controlled to minimize its toxic effect.

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.

Cinnabar induces renal inflammation and fibrogenesis in rats.

The purpose of this study was to investigate whether cinnabar causes renal inflammation and fibrosis in rats. Rats were dosed orally with cinnabar (1 g/kg/day) for 8 weeks or 12 weeks. The control rats were treated with solvent (5% carboxymethylcellulose solution) over the same time periods, respectively. Renal mercury (RHg), urinary mercury (UHg), serum creatinine (SCr), urine kidney injury molecule 1 (KIM-1), renal pathology, and renal mediators were examined. At both 8 weeks and 12 weeks, RHg, UHg, and urine KIM-1 were significantly higher in the cinnabar group than in the control group, although SCr was unchanged. Kidney lesions in the cinnabar-treated rats occurred mainly in the tubules and interstitium, including vacuolization, protein casts, infiltration of inflammatory cells, and slight increase in interstitial collagen. In addition, mild mesangial proliferation was observed in glomeruli. Moreover, the expression of inflammatory and fibrogenic mediators was upregulated in the cinnabar group. In conclusion, cinnabar may cause kidney damage due to the accumulation of mercury, and renal inflammation and slight fibrogenesis may occur in rats. In the clinic, the potential risk of renal injury due to the prolonged consumption of cinnabar should be considered even though the agent is relatively nontoxic.

Nephrotic syndrome of minimal change disease following exposure to mercury-containing skin-lightening cream.

A 28-year-old female suffered from nephrotic syndrome after a long-term use of mercury-containing, skin-lightening cream. The blood and urinary mercury content of this patient increased with use. Renal biopsy showed minimal change disease. Her symptoms were relieved 6 months after discontinuing use of the cream and receiving sodium dimercaptosulfonate and glucocorticosteroid treatments. Proteinuria disappeared, and blood and urinary mercury levels returned to normal. Previous reports of nephrotic syndrome caused by mercury-containing, skin-lightening creams have mostly been identified as be.ing due to membranous nephropathy. Minimal change disease has been reported in a few case reports published in the English language. Here we report a case of nephrotic syndrome with minimal change disease following exposure to a mercury-containing, skin-lightening cream. We also reviewed relevant published reports to summarize clinical features and treatments and to explore the possible mechanisms involved.

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.

Cinnabar is different from mercuric chloride in mercury absorption and influence on the brain serotonin level.

The toxicity of cinnabar, a naturally occurring mercury sulphide (HgS), has long been referred to soluble mercury chloride (HgCl2 ). To investigate whether the speciation of mercury plays a role in its disposition and toxicity, we hereby investigated and compared cinnabar with soluble HgCl2 and pure insoluble HgS in mice on mercury absorption, tissue distribution and in relation to the biological effects. The male C57BL/6J mice were treated by oral administration of various doses of cinnabar, with 0.01 g/kg of HgCl2 for comparison, or the same dose of cinnabar or pure HgS (0.1 g/kg), once a day for 10 consecutive days. The total mercury contents in serum and tissue (brain, kidney, liver) were measured by atomic fluorescence spectrometer (AFS). The biological effects investigated involved monoamine neurotransmitters (serotonin, 5-HT) in brain as an indicator of therapeutic function, and serum alanine transaminase (ALT) as a marker of hepatic damage, blood urea nitrogen (BUN) and serum creatinine as markers for renal function. The mercury absorption of cinnabar or HgS was much less than that of HgCl2 . The mercury levels in brains of the cinnabar group were only slightly changed and kept in a steady-state with the dose elevated. Cinnabar or HgS suppressed brain 5-HT levels. HgCl2 could not cause any changes in brain 5-HT although the mercury level increased considerably. The results revealed that cinnabar or HgS is markedly different from HgCl2 in mercury absorption, tissue distribution and influence on brain 5-HT levels, which suggests that the pharmacological and/or toxicological effects of cinnabar undertake other pathways from mercuric ions.

Exposure to low dose of cinnabar (a naturally occurring mercuric sulfide (HgS)) caused neurotoxicological effects in offspring mice.

Cinnabar, a naturally occurring mercuric sulfide (HgS), has long been used in Chinese mineral medicine for more than 2000 years. Although mercury is well-known for its toxicity, whether cinnabar induces neurotoxicity, especially in infants and children, is unknown. The purpose of this study was to explore the neurotoxic effects of low-dose of cinnabar (10 mg/kg/day) on developing mice. The results revealed neurobehavioral defects in F1-C-Cin group, which were associated with Hg accumulation, increased NO(x) levels in whole blood, and Na(+)/K(+)-ATPase activities in brain tissues. F1- and F2-Cin-V groups were found to increase brain Hg contents and prominent neurobehavioral defects compared with F1-C-V group, suggesting that the fetal brain was more susceptible to irreversible effects for cinnabar-induced damage. Moreover, F1- and F2-Cin-Cin groups had severely neurobehavioral dysfunctions, closely correlated with the further alteration of NO(x) levels and Na(+)/K(+)-ATPase activities than F1- and F2-C-Cin groups. Effects in F2-Cin-Cin group were more significant than those in F1-Cin-Cin group. In conclusion, this study demonstrates that exposure to low-dose of cinnabar during the perinatal and developmental stages results in irreversible and severe injuries of the neurotoxicity in offspring, and NO(x) and Na(+)/K(+)-ATPase activities may exist potential and useful biomarkers for neurotoxicity-induced by low-doses of mercuric compounds.

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.

Widespread use of toxic skin lightening compounds: medical and psychosocial aspects.

Hyperpigmentation disorders and skin lightening treatments have a significant impact on the dermatologic, physiologic, psychologic, economic, social, and cultural aspects of life. Skin lightening compounds, such as hydroquinone and topical corticosteroids, are often used to treat hyperpigmentation disorders, such as melasma, or lighten skin for cosmetic purposes. Despite their established effectiveness, a multitude of dermatologic and systemic complications have been associated with these agents. Regulatory agencies have also recognized the adverse effects of skin lighteners and many countries around the world now forbid the production and sale of these compounds, although this prohibition has not significantly curtailed distribution. Dermatologists and users of cosmetic products should be aware of the various components in bleaching compounds, their potential adverse effects, and alternative options for skin lightening.