What happen to our mitochondria when we take antibiotic like tetracyclines?

[Ahmed Abdullah]

Some antibiotic kills bacteria by inhibiting their protein synthesis. The idea is that, prokaryotic and eukaryotic protein synthesis machinery is not the same, so we can selectively use antibiotic that inhibit bacterial protein synthesis but not ours. Mitochondrion also known as the powerhouse of the cell, is of prokaryotic origin and is similar to bacteria in a many aspect most importantly both have 70S ribosome - their protein synthetic machinery. So what inhibit bacterial protein synthesis (unspecifically) should also inhibit mitochondrial protein synthesis.

Antibiotic like aminoglycosides, macrolides, and tetracyclines works by inhibiting bacterial protein synthesis. So they should also inhibit mitochondrial protein synthesis ---> impair their function .---> and possibly kill them.
Obviously this should not be right, otherwise these antibiotic would not be here. So my question is how they manage, not to kill the mitochondria or be benevolent on them?

 

[Mkorr]

A general answer could be that the mitochondria have a double membrane that does not easily permit the antibiotics to enter the organelle.

 

[nismaratwork]

I'd add, the drugs generally out there target specific surface proteins that our cells don't rely on as heavily, but there can be some cell-death.

It's hard to answer this without speaking to a specific antiobiotic... Mkorr's answer works for me.

 

[SW VandeCarr]

Tetracylines reversibly block protein synthesis in bacteria and at somewhat higher concentrations in human mitochondria, particularly doxycycline. The clinical significance of this at recommended doses is unknown. Tetracylines have a number of important adverse effects and should not be used in children because of their effect on tooth development. They should only be used for limited periods of time, typically a week. They are first line drugs only for rickettsial diseases like Rocky Mountain spotted fever, and in situations where other agents may not be effective. In fact they have been considered for use at higher doses as chemotherapy in aggressive cancers.

The following link has been cited in other papers although its primary focus was not on tetracyclines. Click on manual download, http://aac.asm.org/cgi/reprint/34/1/167?ijkey=51ec1511576efc40773f34181d7607cb31425ef1

 

[epenguin]

Sorry I can't give an expert answer but just vague memory and biological instinct. But I thought many or most of the antibiotics blocked the growth of bacteria, following which they either self-destruct or the immune system has time to deal with them. For mitochondria, apart from permeability barriers etc. you can get by with the ones you already have - but it is not surprising that it is growing children the most sensitive to unwanted side-effects.

 

[nismaratwork]

Sorry I can't give an expert answer but just vague memory and biological instinct. But I thought many or most of the antibiotics blocked the growth of bacteria, following which they either self-destruct or the immune system has time to deal with them. For mitochondria, apart from permeability barriers etc. you can get by with the ones you already have - but it is not surprising that it is growing children the most sensitive to unwanted side-effects.

That is the usual way, and SW VandeCarr described just that; blocking protein synthesis = no new bacteria, or less, so that the immune system can take over. So, yep... the fate of anyone bacterium isn't the issue, but the growth and reduction of colonies.