Intermittent Fasting Promotes Initial Regeneration from Injury in Mice
An interesting effect of intermittent fasting is here demonstrated in mice. Given a rotator cuff injury, mice undergoing intermittent fasting exhibit improved regeneration, but only in the early stages following injury. The researchers provide evidence for this effect to be mediated by changes in the gut microbiome. Various microbial populations generate metabolites that are connected to a range of cellular activities, so the microbiome is a reasonable place to search for mechanisms related to effects of fasting.
Mice underwent rotator cuff injury were treated with intermittent fasting or fed ad libitum. Fasting began one month before surgery and continued until euthanasia. Fresh feces were collected at 2 weeks before surgery, on the day of surgery, and 2, 4, 8 weeks postoperatively for 16S rRNA microbiome sequencing. Supraspinatus tendon-humerus (SSTH) complex was collected at 2, 4 and 8 weeks after surgery. Biomechanical, radiological and histological analysis indicated that intermittent fasting significantly promoted the repair of rotator cuff injury in the early postoperative period, but significantly inhibited the repair of rotator cuff injury at 4 weeks postoperatively.
16S rRNA microbiome sequencing result showed that P. distasonis was the species with the most obvious reduction in intestinal flora of mice after fasting. Then live P. distasonis was used for repair of rotator cuff injury, with equal amount of pasteurized P. distasonis (KPD) or sterile anaerobic phosphate buffer saline (PBS) as control. Biomechanical, radiological, histological analysis were used to assess the effect of rotator cuff repair. The results indicated that the live P. distasonis (LPD) significantly impaired the biomechanical properties, bone regeneration and fibrocartilage regeneration postoperatively.
I was about to write a comment complaining about your vague use of the term "intermittent fasting" without specifying whether this was time restricted feeding, multi-day water only, or something else. However, upon reviewing the paper to figure out what was actually done I find that the authors don't actually specify what their fasting regimen was! The closest they come is this statement way down in the discussion:
> Fasting includes calorie restriction, time-restricted feeding, and intermittent fasting, of which the latter is a combination of the former two.
Unfortunately, without knowing what kind of fast this was, it is difficult to put it to much use in terms of better understanding things as TRF has vastly different effects than multi-day water-only fasts (and I would be surprised if TRF had a significant impact over CR, which I don't think they compared in this study).