In this video we discuss about the original article.

1. Presented by: María Ángela Mejía
Vásquez and Andrés Felipe
Montoya Pizano
3rd semester,
Medicine.
Universidad Pontificia Bolivariana

2. Introduction
Oxidative Stress
Oxidation is a biochemical process of loss of electrons associated with another of reception called
reduction. This process is essential for life, because it takes part in the production of cellular energy.
Oxidative stress appears when oxidation is excessive and there is an overproduction of oxygen free
radicals. If the production of free radicals exceeds the antioxidant capacity, oxidative stress and cell
damage occurs
Some diseases:
● Type 2 diabetes mellitus
● High blood pressure
● Aging
● Atherosclerosis
● Cancer...among others

3. Insulin signalling in cardiac tissue
Insulin can have effects that
oppose vasodilator actions
of NO
Insulin resistance or type 2 diabetes
alters the systemic and neurohumoral
milieu leading to changes in metabolism
and signaling pathways in the heart that
may contribute to myocardial
dysfunction.

4. Objective:
“To evaluate the effects of oxidative stress on insulin signaling in
cardiac tissue of obese mice”

5. Methods
Dichlorodihydrofluorescein
● Is the most widely used fluorescent probe for the measurement of
intracellular ROS, but it is not specific for detection of endosomal ROS
● The oxidation of the 2’7’ dichlorohydrofluorescein diacetate (DCFH-DA)
through the cells causes difluorescein fluorescence (DCF), which can easily
be read in a spectrophotometer.

6. Methods
Nitric oxide formation indicator
● NO has multiple cellular molecular targets. It influences the activity of
transcription factors, modulates upstream signaling cascades, mRNA stability
and translation, and processes the primary gene products.
● The reaction product of nitric oxide with superoxide generates potent
oxidizing agent, peroxynitrite which is the main mediator of tissue and cellular
injury.

7. Methods
Fasting blood glucose
The test was done at the end of the experimental period. Food was removed 6 hours prior to
the test. Blood glucose was measured using a glucometer and results were expressed as
mg/dL
This test was done to observe blood glucose levels and to confirm the induction of insulin
resistance in obese mice and to verify a possible improvement in the treated animals.

8. Methods
Western Blotting
● The western is a test that is based on the detection of a reaction between an antigen
and an antibody, in the study an electrophoresis was done to separate the proteins that
were in the sample and then identify them with specific primary antibodies.
● This method was used to evaluate the signaling of insulin in the heart tissue in order to
identify the action of the NAC (N–acetylcysteine)

9. Results

10. Results

11. Results (figure 1)

12. Results (figure 2)

13. Discussion

14. Conclusions
● Biology and its study allows us to know more techniques to evaluate the cause-effect
relationship between oxidative stress and insulin resistance and the possible resulting
physiological alterations.
● Understanding biological methods and their application in the medical field helps us to
find better treatments and solutions for very common diseases that affect the
population such as insulin resistance
● All medical discoveries are supported by methods and studies based on molecular
biology and their application in laboratories