Significantly increased expression of type-I collagen in tissues from animals treated with IGF-I. (A: Left) Immunohistochemistry shows increased staining for type I collagen in ambulatory tissues when compared to Sham, while hindlimb unloaded tissues show no increase. In tissues from ambulatory and hindlimb unloaded animals treated with IGF-I type I collagen staining is increased. GH+IGF-I also results in increased collagen expression in unloaded tissues. (A: Right) Thresholded images utilized for quantitative analysis of expression. (B) Quantitative analysis of type I collagen expression. Ambulatory healing (Amb + Sal) tissue had significantly more collagen expression when compared to sham tissues (** p = 0.0002) while unloaded tissues did not. GH showed no significant increase between saline treated animals. Ambulatory IGF-I treated animals had significantly (*) increased type-I collagen protein expression (p = 0.0018) when compared to ambulatory animals treated with saline. Tissues from GH+IGF treated ambulatory and hindlimb unloaded animals had significantly (# p = 0.0006 and p = 0.0005, respectively) increased collagen expression when compared to hindlimb unloaded tissues given saline.