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Frank Wolf Pittsburgh Central Catholic High School Grade 11 PJAS 2010
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What is TE? ◦ The development and manipulation of artificial implants, laboratory-grown tissues, genetically engineered cells and/or molecules to replace or support the function of defective or injured parts of the body Why is TE important? ◦ It has the potential to replace or supplement the function of tissues destroyed or compromised in any variety of ways, including: Inherent design flaws Hereditary/congenital defects or conditions Disease Trauma Damage from an individual’s environment Aging TE has great potential for muscle therapy.
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Cells ECM Hormones Blood Supply Defect Regeneration Phil Campbell, Carnegie Mellon
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Direct Physical Trauma ◦ Laceration – cutting of tissue ◦ Contusion - bruise ◦ Strain – “pulling a muscle” Biological (Inherited Abnormalities) ◦ Muscular Dystrophies ◦ Neurological ◦ Storage Diseases
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Main male sex hormone Produced in the sex organs and adrenal cortex of the adrenal gland Steroid hormone of the androgen group ◦ Steroid hormone – passes through cellular and nuclear and affects transcription ◦ Androgen – any hormone that stimulates/maintains male characteristics in vertebrates Acts by binding to androgen receptor ◦ Androgen receptor – transcription factor Stimulates myoblast formation (cell differentiation) Particular testosterone molecule used: testosterone C-III ◦ Anabolic steroid Drug meant to mimic the effects of bodily-produced testosterone Increases skeletal muscle mass
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Subclone of the mus musculus (mouse) myoblast cell line. Differentiates rapidly, forming contractile myotubes and produces characteristic muscle proteins. Mouse stem cell line is used as a model in many tissue engineering experiments. Useful model to study the differentiation of non- muscle cells (stem cells) to skeletal muscle cells. Expresses muscle proteins and the androgen receptor (AR). ◦ AR- DNA binding transcription factor which regulates gene expression.
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The purpose of this study is observe the effects of the anabolic steroid testosterone C-III on the proliferation, differentiation, and survivorship of C2C12 stem cells.
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Alternative Hypothesis: The addition of testosterone C-III WILL affect the proliferation, differentiation, and survivorship of C2C12 stem cells. Null Hypothesis: The addition of testosterone C-III WILL NOT affect the proliferation, differentiation, and survivorship of C2C12 stem cells.
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Cryotank 75mm 2 tissue culture treated flasks Twenty 25 mm 2 tissue culture treated flasks Fetal bovine serum (FBS) C2C12 Myoblastic Stem Cell Line Trypsin-EDTA Pen/strep Macropipette + sterile macropipette tips (1 mL, 5 mL, 10, mL, 20 mL) Micropipettes + sterile tips DMEM Serum - 1% and Complete Media (4 mM L-glutamine, 4500 mg/L glucose, 1 mM sodium pyruvate, and 1500 mg/L sodium bicarbonate + [ 10% fetal bovine serum for complete]) Testosterone C-III 1 M stock solution 75 mL culture flask Incubator Nikon Inverted Microscope Aspirating Vacuum Line Laminar Flow Hood Laminar Flow Hood UV Sterilizing Lamp Labeling Tape Hemacytometer Sterile PBS Ethanol (70% and 100%) Distilled water
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A 1 mL aliquot of C2C12 cells from a Cryotank was used to inoculate 30 mL of 10% serum DMEM media in a 75mm 2 culture flask yielding a cell density of approximately 10 6 to 2x10 6 cells. The media was replaced with 15 mL of fresh media to remove cryo-freezing fluid and incubated (37° C, 5% CO 2 ) for 2 days until a cell density of approximately 4x10 6 to 5x10 6 cells/mL was reached. The culture was passed into 3 flasks in preparation for experiment and incubated for 2 days at 37° C, 5% CO 2.
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After trypsinization, cells from all of the flasks were pooled into 1 common 75mm 2 flask (cell density of approximately 1 million cells/mL). 0.1 mL of the cell suspension was added to 20 25 mm 2 tissue culture treated flasks containing 5 mL of DMEM (com) media, creating a cell density of approximately 10 5 cells per flask. The 1 M stock solution of testosterone C-III was created using 1 mL of ethanol and 0.28842 grams of testosterone C-III. The 10 -6 M, 10 -7 M, and 10 -8 M concentrations were created from the stock, where 10 -6 M is the suggested working concentration of the steroid. The 3 experimental groups and the control group were created by adding: 20 µl of the 10 -6 M solution to 5 flasks (Group A) 20 µl of the 10 -7 M solution to 5 flasks (Group B) 20 µl of the 10 -8 M solution to 5 flasks (Group C) 20 µl of ethanol to 5 flasks (Control) The cells were incubated at 37°C, 5% CO 2 for the remainder of the study. Three flasks from each group were used in the Proliferation Experiment and two flasks from each group were used in the Differentiation Experiment.
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Day 1 and Day 6 ◦ Using the Nikon Inverted Microscope, images of two representative areas of each flask were taken. ◦ Using one flask from each group, cell densities were determined as follows: The cells were trypsinized and collected into cell suspension. 25 µl aliquots were transferred to a hemacytometer for quantification (six counts per flask). Day 1 Using the Nikon Inverted Microscope, images of two representative areas of each of the flasks were taken. Day 2 The original media was removed and replaced with 1% DMEM media (serum starvation) to induce myotube differentiation. Day 6 Using the Nikon Inverted Microscope, images of eight representative areas of each of the flasks were taken.
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ANOVA ◦ p-value: 1.78E-08 ◦ REJECT NULL ◦ Significant variation Dunnett’s Test ◦ 0.05 t-critical value: 2.71 Groupt-valueVariation 10 -6 M9.82Significant 10 -7 M3.11Significant 10 -8 M1.19Insignificant
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Day 1Day 6
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Day 1Day 6
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Day 1Day 6
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Day 1Day 6
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Control Group A Group CGroup B
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Results Consistent with Prior Study Proliferation Experiment ◦ From the ANOVA and the subsequent Dunnett’s tests, the addition of testosterone C-III induced a statistically significant increase in proliferation in the C2C12 cells when it is added at its suggested working concentration, 10 -6 M, and one tenth this concentration, 10 -7 M. Differentiation Experiment ◦ From the qualitative analysis of the images gathered from the flasks, it appears that the addition of testosterone C-III induced myotubule formation. This was especially apparent in the 10 -6 M, while the 10 -7 M and 10 -8 M concentrations showed less dramatic differentiation in comparison.
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Proliferation Experiment – some cell clumping occurred during passage, and counts were lower than expected Differentiation Experiment ◦ Evaluation of images – qualitative and imprecise ◦ Solution – quantitative differentiation assay, e.g. MyoD tagging, myosin/nuclear staining ratio, etc. Evaluate concentrations of testosterone C-III greater than suggested dosage to determine if the steroid is hazardous in excess
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Dr. Phil Campbell Conrad M. Zapanta, Ph.D. Biomedical Engineering Laboratory, Carnegie Mellon University Mark Krotec, PTEI C2C12 myoblastoma cell differentiation and proliferation is stimulated by androgens and associated with a modulation of myostatin and Pax7 expression – German Sport University, Cologne, Germany
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