Effect of embedded metal fragments on urinary metal levels and kidney biomarkers in the Sprague-Dawley rat

BACKGROUND

Wounds with embedded metal fragments are an unfortunate consequence of armed conflicts. In many cases the exact identity of the metal(s) and their long-term health effects, especially on the kidney, are not known.

AIM OF STUDY

The aim of this study was to quantitate the urinary levels of metals solubilized from surgically implanted metal pellets and to assess the effect of these metals on the kidney using a battery of biomarker assays.

MATERIALS AND METHODS

Using a rodent model system developed in our Institute to simulate embedded fragment injuries, eight metals considered likely components of an embedded fragment wound were individually implanted into the gastrocnemius muscle of male Sprague-Dawley rats. The rats were followed for 12 months post-implantation with urine collected prior to surgery then at 1-, 3-, 6-, 9-, and 12-months post-implantation to provide a within-subjects cohort for examination. Urinary metal levels were determined using inductively coupled plasma-mass spectrometry and urinary biomarkers assessed using commercially available kits to determine metal-induced kidney effects.

RESULTS

With few exceptions, most of the implanted metals rapidly solubilized and were found in the urine at significantly higher levels than in control animals as early as 1-month post-implantation. Surprisingly, many of the biomarkers measured were decreased compared to control at 1-month post-implantation before returning to normal at the later time points. However, two metals, iron and depleted uranium, showed increased levels of several markers at later time points, yet these levels also returned to normal as time progressed.

CONCLUSION

This study showed that metal pellets surgically implanted into the leg muscle of Sprague-Dawley rats rapidly solubilized with significant levels of the implanted metal found in the urine. Although kidney biomarker results were inconsistent, the changes observed along with the relatively low amounts of metal implanted, suggest that metal-induced renal effects need to be considered when caring for individuals with embedded metal fragment wounds.

Repeated dose (90 days) oral toxicity study of ursolic acid in Han-Wistar rats

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Ursolic acid was administered at a dose of 100, 300 or 1000 mg/kg/day.

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No Ursolic acid related effects were found after administrating orally for 90 days.

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The no observed adverse effect level is likely to be higher than 1000 mg/kg/day.

Background

Ursolic acid (UA) has been used in alternative medicine for decades, and there has been a great interest in its medicinal properties. Despite this increased interest, a detailed long-term toxicity study has not been performed. The objective of this study was to determine the long-term toxic effect of UA on clinical chemistry, haematology, coagulation, pathology/morphology, behaviour and motor skills in rats.

Methods

A solution was made by dissolving UA in a mixture of 0.1% Tween 80 and 0.5% hydroxypropyl methylcellulose in Milli-Q Water. The control group received the vehicle, and the test groups received a dose up to 1000 mg/kg/day via oral gavage. The solution was administered to both male and female (Han-Wistar) rats for 90 consecutive days.

Results

UA did not cause any deaths, abnormal body weights or abnormal pathology at all test doses. In addition to that, no toxicological changes were observed in behaviour, neurotoxicity, coagulation, haematology or clinical chemistry that are related to the administration of UA.

Conclusion

This study indicates that oral dosing of UA for 90 consecutive days does not lead to toxic effects at any of the doses. Therefore, the NOAEL for UA is likely to be higher than 1000 mg/kg/day.

Mesenchymal stem cells cultured under hypoxic conditions had a greater therapeutic effect on mice with liver cirrhosis compared to those cultured under normal oxygen conditions

Background

Mesenchymal stem cells (MSCs) can be easily expanded. They can be acquired from medical waste such as adipose and umbilical cord tissues, are influenced by culturing conditions, and exert anti-inflammatory, antioxidant, anti-fibrotic, and angiogenic effects. We analyzed the multi-directional effects of MSCs cultured under hypoxic conditions and their underlying mechanisms in the treatment of liver cirrhosis in a mouse model.

Methods

Human bone marrow-derived MSCs cultured under hypoxic (5% O₂; hypoMSCs) and normoxic (21% O₂; norMSCs) conditions were compared by cap analysis of gene expression (CAGE) with or without serum from liver cirrhosis patients. The therapeutic effects of MSCs, including serum liver enzyme induction, fibrosis regression, and hepatic oxidative stress, were evaluated by injecting 1 × 10⁶, 2 × 10⁵, or 4 × 10⁴ MSCs/mouse into the tail veins of mice with carbon tetrachloride (CCl₄)-induced liver cirrhosis. Intravital imaging was performed with a two-photon excitation microscope to confirm the various MSC migration paths to the liver.

Results

CAGE analysis revealed that the RNA expression levels of prostaglandin E synthase (Ptges) and miR210 were significantly higher in hypoMSCs than in norMSCs. In vivo analysis revealed that both hypoMSCs and norMSCs reduced serum alanine aminotransferase, oxidative stress, and fibrosis compared to that in control mice in a dose-dependent manner. However, hypoMSCs had stronger therapeutic effects than norMSCs. We confirmed this observation by an in vitro study in which hypoMSCs changed macrophage polarity to an anti-inflammatory phenotype via prostaglandin E2 (PGE2) stimulation. In addition, miR210 reduced the rate of hepatocyte apoptosis. Intravital imaging after MSC administration showed that both cell types were primarily trapped in the lungs. Relatively a few hypoMSCs and norMSCs migrated to the liver. There were no significant differences in their distributions.

Conclusion

The therapeutic effect of hypoMSCs was mediated by PGE2 and miR210 production and was greater than that of norMSCs. Therefore, MSCs can be manipulated to improve their therapeutic efficacy in the treatment of liver cirrhosis and could potentially serve in effective cell therapy. MSCs produce several factors with multidirectional effects and function as “conducting cells” in liver cirrhosis.

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HypoMSCs decreased liver damage and fibrosis in mice in a dose-dependent manner.

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HypoMSCs produced more PTGES and miR-210 than norMSCs.

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HypoMSCs reduced oxidative stress more effectively than norMSCs.

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HypoMSCs induced anti-inflammatory macrophage growth via prostaglandin E2 production.

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miR-210 reduced hepatocyte apoptosis.