Preferential and non-selective cyclooxygenase inhibitors reduce inflammation during lipopolysaccharide-induced synovitis.

The research examines the comparison of two anti-inflammatory drugs, etodolac and phenylbutazone, which are used to alleviate synovitis inflammation in horses. The result demonstrated that both drugs are capable of reducing inflammation, but etodolac is noted to be a more selective anti-inflammatory agent.

Introduction and Objective

• The research study centers on understanding the efficacy of two non-steroidal anti-inflammatory drugs (NSAIDs), etodolac and phenylbutazone, in treating Synovitis, a condition of inflammation of the synovial membrane, affecting horses.
• The main objective was to compare the anti-inflammatory effects of two NSAIDs. Etodolac is known to selectively inhibit cyclooxygenase isoform COX-2, involved in inflammation. On the other hand, phenylbutazone is a non-selective COX inhibitor affecting both COX-1, which helps in maintaining gastric mucosal integrity, and COX-2.

Methodology

• The study involved 3 groups of horses, each comprising of 6 members. One group was left untreated to serve as a control, while the other two received either etodolac or phenylbutazone injections after being induced with synovitis via a lipopolysaccharide (LPS) injection.
• The dosages for phenylbutazone and etodolac were 4.4 mg/kg and 23 mg/kg respectively. Synovial fluid was extracted and analyzed at two different time intervals, 6 and 24 hours post LPS injection.

Results & Findings

• The results showed that both phenylbutazone and etodolac were successful in significantly reducing white blood cell count, a known indicator of inflammation, 6 and 24 hours following the introduction of LPS, in comparison to the untreated group of horses.
• Further, both drugs also significantly decreased PGE2 levels, a biomarker for inflammation, 6 hours post LPS injection.
• An interesting outcome was that phenylbutazone resulted in a notable reduction of the probable COX-1 prostanoid TXB2, not seen in horses treated with etodolac. This indicates that etodolac doesn’t impact COX-1 as much, hence it can provide safer anti-inflammatory treatment with fewer potential side effects related to gastrointestinal disruption caused by COX-1 inhibition.

Conclusion

• The research evident that both anti-inflammatory drugs effectively reduce inflammation in horses with synovitis.
• However, as etodolac demonstrated a more targeted action towards the COX-2 pathway, with fewer side effects linked to COX-1, it could hence be suggested as the preferred treatment alternative for equine synovitis over phenylbutazone.