Weapon cells have nothing to do with it, how woild that cause u to take more damage? Actually, I don't think ammo has been refered to as cells ingame since they merged light and heavy ammo.
The ring description is clearly talking about your bodies cells. The damage should be (mob dam - armour) * multiplier and NOT mob dam * multiplier - armour.
For me, there is nothing clear and logical in this description. My English is not good and often I use the translator. But in most cases I follow the general context. In this case, this sentence is curious in translation, because it would also mean "animal cage" to me.
On the other hand, following the context, I would never come to the conclusion that this sentence has anything to do with greater damage caused by mob.
Rather, if it is clear to you that it refers to the cells of the body, then it is much more logical to associate with the HP of the avatar, but in no way does it make sense to refer to greater damage taken by the mob. I mean anti regeneration or simply reduction of HP periodically, which prompts you to heal yourself.
So in conclusion from the submitted information about the Critical bonuses and the faster reload, plus that the item is from Mayhem, which are associated with rewards that increase our productivity in the game, my understanding was that the bonus refers to the reduction of ammunition.
Then I read the description of the subject, which gave me food for thought, that it has 1 ped and is L type. That is, I assumed that there is a large decay and it is likely to be used only once or just few times.
But again, this sentence has nothing to do with increasing the blows we would suffer from a mob or another player in the PVP. "Your defenses are weakening..." it would mean exactly what you are saying, but not "Your cells are weakening...". Therefore, I think it's another stupid pun and thats why I think this ring is just a joke from their end.