The Effects of Anti-inflammatory Drugs on Histologic Findings of the Experimental Prolotherapy Model

ABSTRACT

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.