Green Tea and Glycine Modulate the Activity of Metalloproteinases and Collagen in the Tendinitis of the Myotendinous Junction of the Achilles Tendon.

The myotendinous junction (MTJ) is the weakest element in the muscle-tendon unit of the heel, and thus the most susceptible to injuries. The scarcity of adequate treatments means that tendinitis is a major concern to athletes and other groups who depend on their physical fitness, although green tea and glycine have both been shown to have beneficial effects on the inflammation. The present study investigated the remodeling effects of green tea and glycine in the MTJ of rats with tendinitis. For this, male Wistar rats were divided into five groups: animals without tendinitis and animals with tendinitis; animals with tendinitis supplied with green tea; animals with tendinitis supplied with a glycine diet; animals with tendinitis supplied with a green tea and glycine diet. Tendinitis was induced and the treatment with green tea (700 mg/kg/day) and a 5% glycine diet lasted 7 days. The treatments regulated the activity of metalloproteinases (MMP)-2, -8, and -9, and induced the synthesis of type I collagen, glycosaminoglycans, and non-collagenous proteins. Changes were also noted in the compaction of the collagen molecules and the amount of tenocytes. When combined, green tea and glycine modulated the inflammatory process and induced the synthesis of the elements involved in the post-lesion recovery of the tissue. The data from the MTJ were different when compared with results already published using the whole Achilles tendon. These data indicate that each region of the inflamed tendon can exhibit different responses during the treatment and therefore, modify its extracellular matrix components to facilitate recovery and repair. Anat Rec, 299:918-928, 2016. © 2016 Wiley Periodicals, Inc.