Metalloproteinase inhibitor GM6001 delays regeneration in holothurians

The effect of the GM6001 metalloproteinase inhibitor on the regeneration of ambulacral structures in Eupentacta fraudatrix has been investigated. Inhibition of proteinase activity exerts a marked effect on regeneration, being dependent on the time when GM6001 is injected. When administration of the inhibitor begins on day 3 post-injury, regeneration is completely abolished, and the animals die. This means that early activation of proteinases is crucial for triggering the regenerative process in holothurians. When GM6001 in first injected on day 7 post-injury, the regeneration rate decreases. However, this effect has proven to be reversible: when inhibition ceases, the regeneration resumes. The effect of the inhibitor is manifested as a retarded degradation of the extracellular matrix, the lack of cell dedifferentiation, and, probably, a slower cell migration. The gelatinase activity is detected in all the regenerating organs of E. fraudatrix. In the holothurian Cucumaria japonica, which is not capable of healing skin wounds and ambulacrum reparation, no gelatinase activity was observed at the site of damage. A suggestion is made that proteinases play an important role in regeneration in holothurians. The most probable morphogenesis regulators are matrix metalloproteinases with gelatinase activity.