Apoptosis在线视频

OK today we will learn apoptosis together

We've learned the damage of tissues and cells

which is divided into reversible and irreversible damage

Then there are two major categories of irreversible damage

one is necrosis

and the second major category is apoptosis

Well what is apoptosis

It refers to such a kind of death

that occurs during the development of the body's cells

or under the influence of certain factors

by the regulation of genes

and its products in the cell

This kind of death involves single cells

which forms apoptotic bodies

Unlike necrosis

it does not cause inflammation in surrounding tissues

Well from this concept we also see

this kind of apoptosis can occur either under physiological conditions

or under pathological conditions

So what is the significance of apoptosis

Under physiological conditions

apoptosis plays an important role

in embryonic and tissue development

the stability of normal cell populations

in the tissue body defense and immune response

injury aging and tumorigenesis

For example if there is too much apoptosis

we know that AIDS

CD4 positive T cells in its patients have too much apoptosis

then without such T cells

patients are prone to various infections

and tumors

There is a second category such as transplant rejection

if immunosuppressants is no longer taken after the transplant

Then the body will undergo transplant rejection

resulting in transplanted organ apoptosis

There is also apoptosis during

ischemia-reperfusion

Neurological degenerative diseases

such as Alzheimer's disease

brain nerve cell apoptosis may occurs

Electric radiation also causes increased apoptosis

So what does too little apoptosis cause

Tumorigenesis

The reason why the tumor can be unlimitedly proliferated

without being controlled by the body

then it is related to too little apoptosis

We can use this principle to induce apoptosis

which can be meaningful

for the prevention and treatment of tumors

In addition there is less apoptosis in autoimmune diseases

apoptosis of cells also decreases during virus infection

Let’s focus on the morphological changes of apoptosis

We can see in the apoptotic tissue

that it is the death of a single cell

however inflammation is the death of a group of cells

It involves a single cell

which is in a separate state

with surrounding normal cells

generally round Red-stained cytoplasm

Its chromatin is aggregated into small clumps

and is very characteristic. You can't find any inflammatory cells around it

and it does not trigger an inflammatory reaction

Then under the electron microscope we can see that

its chromatin characteristically gathered at the edge of the nuclear membrane

and then

The cell membrane gradually buds and falls off

forming apoptotic bodies

Inside these apoptotic bodies

some of the complete structure of the organelles can be seen

This is its pathogenesis

Exogenous and endogenous factors induce apoptosis

and this process is completed

through the Caspase family

Then after the chromatin accumulates under the nuclear membrane

the cell membrane sprouts

and then surrounds many organelles

then apoptotic bodies form

Apoptotic bodies can finally be engulfed by macrophages

to be degraded

There is a very characteristic change in apoptosis

When apoptosis occurs if we perform

agarose gel electrophoresis

there will be a characteristic DNA gradient change

The bands are like ladders

and they are all DNA fragments

with an integer multiple of 180 to 200 bp

Why is this

Since endonuclease is activated

during apoptosis

endonuclease cuts chromatin

between nucleosomes

so such DNA fragments

with an integer multiple of 180 to 200 bp

will be produced

So agarose gel electrophoresis shows

a gradient of DNA

Then it is important that we distinguish

the difference between apoptosis and necrosis

Apoptosis must be seen in pathological damage

however apoptosis can occur both under physiological conditions

and under pathological conditions

Necrosis involves many cells

while apoptosis involves single cells

During apoptosis

the cell's cytoplasm shrinks

the mitochondria are very dense

other organelles are also dense

and the chromatin is also dense without being damaged

Especially the cell membrane because it is in the form of budding is also intact

because of budding it is also intact

Because of these above

the cytoplasmic components will not be released

so there is no inflammatory reaction around it

On the contrary when necrosis occurs the cell membrane is destroyed

the organelles are destroyed

and the components in the cytoplasm are released into the surrounding tissue

so it will cause an inflammatory reaction

This is a schematic diagram a normal hair cell

When a normal cell is necrotic you can see the swelling of mitochondria

the swelling and breakage of endoplasmic reticulum etc

Finally the cell membrane is destroyed

Then when apoptosis occurs it is in the form of budding

and the organelles are intact

apoptotic bodies surround

Chromosome fragments

and some complete organelle structures

This is called apoptosis

OK today's lesson is over thank you