Age-related differences in prostaglandin E2 synthesis by equine cartilage explants and synoviocytes.

The research paper investigates the varying sensitivity of equine cartilage and synoviocytes (cells forming the synovial fluid in horse joints) to Lipopolysaccharide (LPS), and the resultant prostaglandin E2 (PGE2) synthesis. This is examined across three age groups, with the oldest age group (above 20 years) showing the highest sensitivity in cartilage and lowest in synoviocytes.

Objective of Research

• The primary objective of this research was to study the age-dependent variations in the response of horse joint components (cartilage and synoviocytes) to LPS. The reaction to LPS is measured via the synthesis of PGE2, an inflammatory biomarker in osteoarthritis.

Methodology

• PGE2 synthesis was measured in cartilage explants and synoviocytes harvested from horses from three different age groups. The first age group is under 10 years old (group A), the second between 11-20 years (group B), and the third over 20 years (group C).
• The exposure to LPS was undertaken across three-time frames (24, 36, and 48 hours) with LPS concentrations ranging from 1.0 micrograms/mL and higher.

Findings

• Cartilage from the oldest horse group (group C) showed the highest sensitivity to LPS. A significant increase in PGE2 concentration was recorded with LPS exposure of 1.0 micrograms/mL and higher across the tested durations.
• The youngest horse group (group A) showed no reaction to LPS in the cartilage, even with exposure up to 100 micrograms/mL across the same durations.
• In contrast, synoviocytes from the youngest horse group were most sensitive to LPS, producing significant PGE2 increases with exposure to LPS concentrations of 1 microgram/mL and higher at 24 and 36 hours.
• Synoviocytes from the older groups showed a noticeable but smaller increase in PGE2 levels on LPS stimulation.

Conclusion and Implication

• The researchers deduce from their findings that both synoviocytes and chondrocytes (the primary cells in cartilage) play roles in the degenerative changes which occur in cartilage in horses with osteoarthritis. The PGE2 concentration increase resulting from LPS stimulation shows age-dependent variability, and the high concentrations are potentially damaging for cartilage health.