The Effect of Butyric Acid on Normal Tendons: A Potential Stimulus for Extracellular Matrix Expression

We propose comparing angiogenic effects of butyric acid (BA)–impreg­nated suture vs control suture on an aged tendon model.

Twenty-four 3-year-old rabbits under­went bilateral Achilles tendon expo­sure. BA-impregnated orthopedic suture was sutured into one side, and a control orthopedic suture into the contralateral side similarly. The rabbits were sacrificed at 7, 30, and 45 days and the tendons harvested for gross, histologic, and biochemical study.

Histologically, there was increased vascularity/cell migration at all time points in the BA-treated tendons; pro­teoglycan expression (ie, safranin O staining) increased at 30 and 45 days. DNA concentration was significantly (P = .05) higher in the BA-treated tendon group relative to the control group at 7 days but was unchanged at 30 and 45 days. Similarly, mes­senger RNA (mRNA) expression of vascular endothelial growth factor (VEGF) was significantly (P = .05) higher in the BA-treated tendon at 7 days. A trend (P = .12) for higher expression in the BA group also was found at 30 days.

BA-treated tendons showed significantly increased angiogenic activity 7 days after surgery, as well as cell proliferation. This was seen with increased mRNA expression of VEGF and with increased DNA concentration. This continued for up to 30 days, leveling off by 45 days.

Much of tendon repair and reconstruction in orthopedics is centered on repairing compromised tendons—tendons with tendinosis or significant degenerative problems before the tear or rupture occurred. By enhancing this repair with biological stimulation, as demonstrated in this BA suture study, we may effectively improve results of tendon repair, such as in the older rotator cuff population.