In mice you can come close by combining the Ames mutant with calorie restriction (Bartke et al. 2001).
Bartke, A., Wright, J.
C., Mattison, J. A., Ingram, D. K., Miller, R. A., & Roth, G. S.
(2001). Longevity: extending the lifespan of long-lived mice. Nature, 414(6862), 412-412.
In rats I don’t know of extension close to Bartke et al. 2001 or the olive oil/C60 experiments. The C60 experiment really needs to be repeated preferably by a group with considerable rodent lifespan experience.
On Sat, Jan 31, 2015 at 1:10 PM, Walter Derzko wrote:
Maximum Lifespan of rats?
A naive question–Are there any other natural /or synthetic substances /protocols that can double the normal life span of rats or provide even better longevity results?
In a 2012 primary study at the University of Paris, an olive oil / carbon  or C60 suspension was administered to rats by intra-peritoneal administration or oral gavage. Researchers prolonged the lifespan to almost double the normal lifespan of rats (from ~17-37 months to ~60-66 months) and significant toxicity was not observed.
The prolongation of the lifespan of rats by repeated oral administration of  fullerene
N.B. These researchers used an olive oil /C suspension here because they did not know how to dissolve pristine C in water, which is now possible.