Background  Skin wound caused by injury or disease can lead to multiple complications or even death. How to construct wound dressing that can effectively promote hemostasis, healing and repair is a key problem to be solved urgently.

  Objective  To observe the effect of hydroxybutyl chitosan (HBC) combined with biosilica (BS) composite hydrogel dressing on the repair of full-thickness skin wound in mice.

  Methods  Twenty 9-week-old male C57BL/6J mice were treated with full-thickness skin wound models of 6mm in diameter on the left and right sides of the back, which were fixed with silica gel plates to prevent wound contraction. The mice were randomly divided into group A and group B. The wounds on the right side of group A were HBC/BS group (experimental group). The left wounds of mice in group A were blank control group. The right wounds of mice in group B were carboxymethylcellulose sodium (CMC-Na)/propylene glycol (PG) group, and the left wounds of mice in group B were HBC group. Every mouse was raised in a single cage, and all wounds were routinely disinfected every 3 days and fixed plates were replaced. After disinfection, the blank control wounds were directly covered with breathable transparent film, while wounds in other groups were evenly coated with corresponding hydrogel drug for 200 mg, and then covered with breathable transparent film. Wound bleeding and healing in each group were continuously observed. Wound tissue samples were taken from half of the mice in each group at 15 d and 21 d. HE staining, Masson staining and BrdU immunofluorescence staining were performed, and the hydroxyproline content in wound tissue was detected.

  Results  The wound healing rates of the experimental group were significantly higher than those of the blank control group at 3 d, 6 d, 9 d, 12 d and 15 d after modeling (P < 0.01), and were significantly higher than those of the CMC-Na /PG group at 3 d, 6 d and 9 d (P < 0.01). There was no significant difference in the wound healing rate between the experimental group and the HBC group at all time points (P > 0.05). Pathological observation suggested that at 15 d and 21 d after modeling, the wound surface of the experimental group and the HBC group was closer to the structure of normal skin, the epithelium was intact and dense, and the collagen fibers were uniform and orderly. The distribution density and structural integrity of skin appendages in the experimental group were better than those in other groups. At 15 d after modeling, the hydroxyproline content of wound tissue in experimental group was higher than that in blank control group and CMC-Na /PG group (P<0.05), but there was no significant difference between experimental group and HBC group (P>0.05). At 21 d after modeling, there was no significant difference among groups (P>0.05).

  Conclusion  Compared with CMC-Na /PG hydrogel that has been applied in clinical practice, HBC/BS hydrogels and HBC hydrogels have better effect on promoting wound healing. Composite hydrogel with BS can effectively promote the regeneration and repair of skin appendages, and it has a more comprehensive ability to promote wound repair and healing compared with HBC hydrogel.