Table 1.
Cell types and variable meaning.
| Variable | Description |
|---|---|
| CU | Healthy unsignaled chondrocytes |
| CT | Chondrocytes signaled by DAMPs to become catabolic |
| CE | Chondrocytes that produce EPO |
| ST | Catabolic cells that release PIC and ROS |
| SA | EPOR-active cells, can switch back to CU if signaled by EPO |
| DN | Necrotic cells. Formed by initial strain, release DAMPs |
| DA | Apoptotic cells, not included in the model |
| R (ROS) | Reactive oxygen species. Signal CE cells to release EPO |
| M (DAMPs) | Damage-associated molecular patterns. Alarmins released by DN and the ECM as a result of the impact |
| F (PIC) | Pro-inflammatory cytokines. Signal healthy cells to become catabolic and catabolic cells to become apoptotic. Degrade the ECM |
| P (EPO) | Erythropoietin. Anti-inflammatory cytokine. Diminishes the effects of inflammation |
| U (ECM) | Extracellular matrix. Chondrocytes live within it. Subject to degradation from the stress application and PIC |