STUDY: Mercury-Induced Externalization of Phosphatidylserine and Caspase 3

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Although this is a marine biology study I found there was information

related to human toxicity. Being concerned with the effects of mercury

co tent in vaccines, I felt it was relative to my understanding and

concerns. Others that share the same concern may find this study

informative.

 

http://www.mdpi.org/ijerph/papers/ijerph2006030005.pdf

 

Mercury-Induced Externalization of Phosphatidylserine and Caspase 3

Activation in Human Liver Carcinoma (HepG2) Cells

Dwayne J. Sutton1 and Paul B. Tchounwou1*

1Molecular Toxicology Research laboratory, NIH-Center for

Environmental Health, College of Science, Engineering and

Technology, Jackson State University, 1400 Lynch Street, Box 18540

Jackson, Mississippi 39217, USA

*Correspondence to Dr. Paul B. Tchounwou. Email: paul.b.tchounwou

Received: 20 October 2005 / Accepted: 24 March 2006 / Published: 31 March 2006

 

Abstract: Apoptosis arises from the active initiation and propagation

of a series of highly orchestrated specific biochemical events leading

to the demise of the cell. It is a normal physiological process, which

occurs during embryonic development as well as in the maintenance of

tissue homeostasis. Diverse groups of molecules are involved in the

apoptosis pathway and it functions as a mechanism to eliminate

unwanted or irreparably damaged cells. However, inappropriate

induction of apoptosis by environmental agents has broad ranging

pathologic implications and has been associated with several diseases

including cancer. The toxicity of several heavy metals such as mercury

has been attributed to their high affinity to sulfhydryl groups of

proteins and enzymes, and their ability to disrupt cell cycle

progression and/or apoptosis in various tissues. The aim of this study

was to assess the potential for mercury to induce early and late-stage

apoptosis in human liver carcinoma (HepG2) cells. The Annexin-V and

Caspase 3 assays were performed by flow cytometric analysis to

determine the extent of phosphatidylserine externalization and Caspase

3 activation in mercury-treated HepG2 cells. Cells were exposed to

mercury for 10 and 48 hours respectively at doses of 0, 1, 2, and 3

¦Ìg/mL based on previous cytotoxicity results in our laboratory

indicating an LD50 of 3.5 ¡À 0.6 ¦Ìg/mL for mercury in HepG2 cells. The

study data indicated a dose response relationship between mercury

exposure and the degree of early and late-stage apoptosis in HepG2

cells. The percentages of cells undergoing early apoptosis were 0.03 ¡À

0.03%, 5.19 ¡À 0.04%, 6.36 ¡À 0.04%, and 8.84 ¡À 0.02% for 0, 1, 2, and 3

¦Ìg/mL of mercury respectively, indicating a gradual increase in

apoptotic cells with increasing doses of mercury. The percentages of

Caspase 3 positive cells undergoing late apoptosis were 3.58 ¡À 0.03%,

17.06 ¡À 0.05%, 23.32 ¡À 0.03%, and 34.51 ¡À 0.01% for 0, 1, 2, and 3

¦Ìg/mL of mercury respectively, also indicating a gradual increase in

Caspase positive cells with increasing doses of mercury.

Keywords: Mercury, Apoptosis, Flow cytometry, HepG2 cells, Caspase 3, Annexin V

 

Below are just a few of the other references sited in this study that

I identified as related to my mercury exposure and vaccine concerns.

To view the full study and complete list of references you must open

the link provided above.

 

 

Sweet, L. I.; Zelikoff, J. F.: Toxicology and

immunotoxicology of mercury: a review in fish and

humans. J. Toxicol Environ. Health B Crit. Rev.,

2001, 2, 161 ¨C 205.

 

Clarkson, T. W.; Magos, L.; Myers, G. J.: The

toxicology of mercury ¨C current exposures and

clinical manifestations. N Engl J Med. 2003, 349,

1731 ¨C 1737

 

Clarkson, T. W.: The three modern faces of

mercury. Environ Health Perspect Suppl.Suppl.1,

2002, 10, 11 ¨C 23.

 

Steuerwald, U.; Weibe, P.; Jorgensen, P.; Bjerve,

K.; Brock, J.; Heinzow, B.; Budta-Jorgensen, E.;

Grandjean, P.: Maternal seafood diet,

Methylmercury exposure and neonatal neurologic

function. J. Pediatr., 2000, 5, 599 ¨C 605

 

Baskin, D. S.; Nago, H.; Didenko, V.: Thimerol

induces DNA breaks, caspase 3 activation,

membrane damage, and cell death in cultured

human neurons and fibroblasts. Toxicological

Sciences, 2003, 74, 361 ¨C 368.

 

U.S. EPA. Mercury study report to congress

volume I. Office of Air Quality Planning and

Standards and Office of Research and Development,

U. S. Environmental Protection Agency, 1997

 

Diamond, G. L.; Zalups, R. K.: Understanding renal

toxicity of heavy metals. Toxicol.Pathol., 1998, 26,

92 ¨C 103.

 

Nielsen, J. B.; Hultman, P.; Mercury-induced

autoimmunity in mice. Environ.Health Perspect.

Suppl. 5, 2002, 110: 877 ¨C 881.

 

Sweet, L. I.; Zelikoff, J. F.: Toxicology and

immunotoxicology of mercury: a review in fish and

humans. J. Toxicol Environ. Health B Crit. Rev.,

2001, 2, 161 ¨C 205.

 

Weed, R.; Eber, J.; Rothstein, A.: Interaction of

mercury with human erythrocytes. Journal of

General Physiology, 1962, 45, 395 ¨C 410.

 

Comparison of neurobehavioral changes I three inbred

strain of mice prenatally exposed to methylmercury.

Neurotoxicology and Teratology, 2000, 22, 397 ¨C 403.

 

Graff, R. D.; Falconer, M. M.; Brown, D. L.;

Reuhl, K. R.: Altered sensitivity of

posttranslationally modified microtubules to

Methylmercury in differentiating embryonal

carcinoma-derived neurons. Toxicol Appl.

Pharmacol., 1997, 2, 215-224.

 

Mary

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In Love, Light and Honor.............. May You and Yours be Blessed

with Health, Happiness, Wisdom and Prosperity.