Abstract:

Objective To investigate the effect of topical oxygen therapy combined with vacuum-assisted closure on the would healing of stage Ⅲ pressure ulcer in guinea pigs, and explore the mechanism. Methods Stage Ⅲ pressure ulcers in the left trochanter major of guinea pigs (n=20) were prepared, and were divided into sequential combined intervention group (－125 mmHg vacuum-assisted closure for 320 min and 5 L/min topical oxygen therapy for 160 min), alternate combined intervention group (－125 mmHg vacuum-assisted closure for 40 min and 5 L/min topical oxygen therapy for 20 min, alternation for 8 times), vacuum-assisted closure group (－125 mmHg vacuum-assisted closure for 40 min, then suspension for 20 min, and repeat for 8 times), topical oxygen therapy group (5 L/min topical oxygen therapy for 20 min, then suspension for 40 min, and repeat for 8 times) and blank control group (conventional treatment for wound, and no vacuum-assisted closure and topical oxygen therapy) according to different treatment for wound. Wound areas were measured and wound shrinkage rates were calculated before wound formation and on the first, third, seventh and eleventh day after wound formation. Skin tissue specimens were collected from the wound, and tissue edema and inflammatory cell infiltration were observed with HE staining under light microscopy. The expression of vascular endothelial growth factor (VEGF) and microvascular density (MVD) in wound tissues was detected with immunohistochemical staining. Results The wound shrinkage rates in sequential combined intervention group and alternate combined intervention group were significantly higher than those in the other groups at the given time point (P<0.01). Histological observation indicated that the tissue edema and inflammatory cell infiltration in wound in sequential combined intervention group and alternate combined intervention group were mild. Immunohistochemistry revealed that the expression of VEGF and MVD in wound tissues in sequential combined intervention group and alternate combined intervention group was significantly higher than that in the other groups (P<0.01). The parameters in alternate combined intervention group were superior to those in sequential combined intervention group. Conclusion Topical oxygen therapy combined with vacuum-assisted closure can rapidly reduce wound inflammation, promote expression of VEGF and MVD in wound tissues, increase wound vascularization, and promote wound healing of stage Ⅲ pressure ulcer in guinea pigs.

Key words: topical oxygen therapy, vacuum-assisted closure, stage Ⅲ pressure ulcer, wound healing, vascular endothelial growth factor, microvascular density