What are the main characteristics of senescent cells?

People will age when they reach a certain age, which is related to senescent cells. Aging is very scary for women, and senescent cells are also related to metabolism. Clinically, senescent cells have key characteristics, and if your metabolism slows down, you should be careful about aging.

Studies have shown that the nucleus, cytoplasm and cell membrane of aging cells have obvious changes:

① The water content in cells decreases, the volume decreases, and the metabolism slows down;

②The activity of intracellular enzymes decreases;

③ Pigments will accumulate in cells;

④ The intracellular respiration rate slows down, the volume of the cell nucleus increases, the nuclear membrane folds inward, the chromatin shrinks, and the color deepens. The number of mitochondria decreased and their size increased;

⑤The permeability function of the cell membrane changes, which reduces the material transport function.

Morphological changes

In general, the various structures of aging cells undergo degenerative changes. The morphological changes of senescent cells are as follows:

1. Nucleus: enlarged, darkly stained, with inclusions in the nucleus

2. Chromatin: condensation, shrinkage, fragmentation, dissolution

3. Plasma membrane: increased viscosity and decreased fluidity

4. Cytoplasm: pigment accumulation, vacuole formation

5. Mitochondria: Decreased number and increased size

6. Golgi apparatus: fragmentation

7. Nissl bodies: disappear

8. Inclusions: Decreased glycogen and fat accumulation

9. Nuclear membrane: invagination

Changes at the molecular level

1. DNA: Generally speaking, DNA replication and transcription are inhibited during cell aging, but some individual genes may be abnormally activated, telomeric DNA may be lost, mitochondrial DNA may be specifically deleted, DNA may be oxidized, broken, deleted and cross-linked, and the degree of methylation may be reduced.

2. RNA: The content of mRNA and tRNA is reduced.

3. Protein: The content decreases, and the intracellular protein undergoes modification reactions such as glycosylation, carbamylation, and deamination, resulting in decreased protein stability, antigenicity, and digestibility. Free radicals cause protein peptides to break, cross-link, and denature. The amino acids change from left-handed to right-handed.

4. Enzyme molecule: The active center is oxidized, metal ions Ca2+, Zn2+, Mg2+, Fe2+, etc. are lost, the secondary structure, solubility, and isoelectric point of the enzyme molecule change, and the overall effect is enzyme inactivation.

5. Lipids: Unsaturated fatty acids are oxidized, causing cross-linking between membrane lipids or between membrane lipids and lipoproteins, and reducing membrane fluidity.