To investigate the effect of PHMB/glycerol gel on chronic wounds and related mechanisms, such as bacterial biofilms and some molecular factors that influence the growth of granulation tissue.

A 2 cm×2 cm skin wound was prepared on the back of 48 BALB/c mice and randomly divided into PHMB/glycerol gel group, Silver ion group, and traditional gauze dressing (control) group, with 16 mice in each group. After 10 and 12 days, 48 of the skin defects were subjected to hematoxylin and eosin (HE) staining, and the morphology of the granulation tissue (capillary blood vessels) was observed. Western blotting and immunohistochemical (IHC) analyses were performed to explore the expression of Toll-like receptors 2 (TLR2), Toll-like receptors 4 (TLR4).

The wound healing time in PHMB/glycerol gel group was significantly shorter than that in Silver ion group and control group [(21.000±1.549) d vs. (25.000±1.773), (31.000±1.195) d, F=32.71, P<0.05, respectively]. Western blotting results showed that the expression levels of TLR2 (126 283±8 675 vs. 65 470±3 106, 27 290±3 698, F=227.60, P<0.001, respectively) and TLR4 (135 698±10 130 vs. 58 488±3 376, 19 152±3 730, F=247.30, P<0.001, respectively) in PHMB/glycerol gel group were higher than in Silver ion group and control group. IHC results showed that the expression levels of TLR2 (47.330±1.783 vs. 24.940±8.226, 17.010±5.028, F=23.15, P<0.01, respectively) and TLR4 (45.160±3.957 vs. 30.940±4.842, 16.060±4.989, F=29.77, P<0.05, respectively) in PHMB/glycerol gel group were significantly higher than those in Silver ion group and control group.

PHMB/glycerol gel can promote bacterial biofilm clearance and granulation tissue growth by increasing TLR2 and TLR4 expression, making it an ideal choice for chronic infectious wound repair.

PHMB/glycerol gel; Bacterial biofilms; Chronic wound; Toll-like receptors 2; Toll-like receptors 4