Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)
Creatures you control that have +1/+1 counters put on them after Inspiring Call resolves won't gain indestructible.
Once a creature gains indestructible, it will have it for the turn, even if it loses all its +1/+1 counters.