I wonder if the water is not playing a role in the 29 month old mice who are showing signs of reversal of age? For instance, water can be structured many different ways, (red light, vortexing, filtering through rock like media). I wouldn’t be surprised if the ultrasound is structuring/energizing the water, and it’s the mice being bathed in this substance that is exerting the effects.
I have heals many maladies in the past simply structuring water and then soaking my feet in that water. For whatever reason that I can only guess about, my best results have always come from using sea-water, (structuring that, and then soaking my feet in that). The results are systemic. A rough patch of skin on say my knee is returned to normal by soaking my feet. An increase in energy, (not driven by cortisol) can be observed by soaking my feet.
I say all of this to say: water may be playing a key role in these findings, (though if ultrasound is capable of structuring fluid, the fluids of the body may suffice too). I just personally have had remarkable success with “bathing” in structured water.