Don't believe that.. I think that Tsunade is going to help Sakura later on, when she tries to revive Sasuke. Jiraiya and Orochimaru are gone and she must follow them also. Tsunade already felt useless, when she couldn't save her little brother or Dan ( her boyfriend ), and if she could deliver a great favor in the end for Naruto and Sakura, then it would be when Sakura tries to save Sasuke from dying.
** It's still an assumption, but I strongly believe that Sasuke will be re-deemed, tries to kill Tobi / Edo Madara with sacrificial jutsu, he fails, Sakura helps him out with a look a like Chijoo jutsu with help of Tsunade.
Who knows; maybe by entering this regeneration jutsu, she will eventually lose her life-force anyway. There could be a huge risk for opening this regeneration jutsu.