First study is saying that trenbolone is altering sensitivity in the muscle cells. I can't see where it is stating that it is increasing FGF production as you are saying. I think you are misinterpreting this information or I am not reading it the same way you are.
I am not saying trenbolone doesn't help, because I know a lot of studies which show tendon/joint healing improvement after surgery when using nandrolone & testosterone. You may want to look into nandrolone instead as trenbolone has a higher toxicity. I don't think there are any studies which show an increase in collagen synthesis specifically by these compounds, but an improvement in recuperation has been shown. Same end result I guess but wording it differently
