Gelatinase activities in wounds of healing-impaired mice versus wounds of non-healing-impaired mice

The gelatinases, matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9), have been implicated in different aspects of wound repair. However, little is kn own about MMP-2 and MMP-9 activity in animal models of impaired wound heali ng. We sought to compare serial gelatinase activities for 25 days after ful l-thickness excisional wounds in genetically diabetic healing-impaired mice and their nondiabetic non-healing-impaired littermates. Wound samples were frozen, homogenized, clarified by centrifugation, and analyzed on zymograp hy gels, and MMP bands were quantitated relative to a conditioned media sta ndard from HT-1080 cells. Gelatinase activity in both diabetic mice and non diabetic mice increased after the mice were wounded. However, levels of lat ent gelatinases peaked earlier in the diabetic wounds, and there was more a ctive MMP-2 and MMP-9 in the wounds of the diabetic mice than in the mounds of the nondiabetic mice. Because the higher gelatinase activity in the wou nds of the diabetic mice was similar to the higher levels of gelatinase rep orted in difficult-to-heal wounds such as ulcers and burns, this diabetic m ouse model may be useful for studies of these proteinases and their inhibit ors in impaired wound healing.