Objective
To investigate the effects of nonsteroidal anti- inflammatory drugs (NSAIDs) and acetaminophen on histologic changes of the Achilles tendon in an experimental prolotherapy model. Method: The right Achilles tendon of 60 rats was injected with 20% dextrose on experimental day 1, 7, and day 14, whereas the left was not injected and used as control. Rats were divided into 3 subgroups: NSAIDs medication group (10 mg/kg/day), acetaminophen medication group (100 mg/ kg/day) and no medication group. Medications were given for 3 consecutive days after each injection. Rats were sacrificed at 3 and 6 weeks after first injection. The transverse diameter of gross specimen, the number of fibroblasts on light microscope, and the distribution of collagen fibril on electron microscope were assessed. Results: The transverse diameter and the count of fibroblasts of all groups increased significantly in the injected tendon compared to the non-injected tendon. However, there were no differences among all groups significantly (p＜0.05). On electron micrograph, fibril diameters of injected tendon consisted of mainly smaller sizes with the intermediate sizes. Conclusion: Prolotherapy enhances fibroblastic stimulation and elaboration of extracellular matrix. Short term use of NSAIDs may not have any adverse effects on tissue proliferation after prolotherapy. (J Korean Acad Rehab Med 2006; 30: 378-384)
