ACETAMINOPHEN CONSUMPTION ALTERS ACHILLES TENDON COLLAGEN CONTENT IN WISTAR RATS

The purpose of this study was to evaluate the influence of acetaminophen (APAP) on collagen content in rat Achilles tendon. Ten‐week‐old male Wistar rats were given saline (SAL, n=8) or APAP (n=10; 200 mg·kg−1) once daily via oral gavage for 8 weeks. Tendon collagen content was determined by detection of the collagen specific amino acid hydroxyproline using HPLC. Following treatment, tendons, mm. gastrocnemius and soleus, fat pad, heart, liver, and femur and tibia bones were harvested. Tendon collagen content was greater (p<0.05) in the rats given APAP (SAL: 510.5±42.3; APAP: 663.4±38.0 μg collagen·mg tendon wet weight). Fat pad weight was greater (p<0.05) in the APAP group (SAL: 11.02±1.87; APAP: 15.83±1.36 g). Both femur and tibia weight [femur: (SAL: 867±19; APAP: 936±23 mg, tibia: (SAL: 644±22, APAP: 718±16 mg)] were greater (p<0.05) in the rats consuming APAP. M. soleus (SAL: 203±11; APAP: 240±9 mg) but not m. gastrocnemius (SAL: 2.73±0.05; APAP: 2.76±0.12 g) weight was greater (p<0.05) in the rats given APAP, whereas heart and liver weight was not different between groups. APAP appears to promote collagen deposition in tendon and has growth promoting affects on bone and skeletal muscle, however, the affect on skeletal muscle appears to be specific to the type I soleus muscle. The specific mechanisms of these effects require further study.