Effect of Dezocine and Dexmedetomidine as Adjuvants in Ropivacaine for Incision Subcutaneous Infiltration Anesthesia on Incision Healing in Diabetic Rats.

INTRODUCTION: Surgery can induce insulin resistance (IR) in diabetic patients, and severe IR compromises the body's ability to combat infection and shock, impairs the provision of high metabolic energy required post-surgery, and delays wound healing. Local infiltration anesthesia is commonly employed for postoperative pain management due to its simplicity, cost-effectiveness, and efficacy. However, research on optimal anesthetic formulations for incisional subcutaneous infiltration anesthesia that promote wound healing in diabetic patients remains limited. This study aims to investigate the effect of dezocine and dexmedetomidine as adjuvants in ropivacaine incision subcutaneous infiltration anesthesia on incision healing in diabetic rats. METHODS: Six groups, each comprising 18 diabetic rats, were randomly assigned. Following wound suturing, 1 mL of liquid was administered as subcutaneous infiltration anesthesia at the incision site. The compositions of the liquids were as follows: Group A received 0.375% ropivacaine, Group B received 0.375% ropivacaine plus 0.05 mg dezocine, Group C received 0.375% ropivacaine plus 0.005 mg dexmedetomidine, Group D received 0.375% ropivacaine plus 0.05 mg dezocine and 0.005 mg dexmedetomidine, Group E received normal saline plus 0.05 mg dezocine and 0.005 mg dexmedetomidine, and Group M received normal saline. The incision healing process was evaluated on Days 3, 7, and 14 post-suturing. CD31 and CD68 expression levels in the incision tissues were quantified using mean optical density (MOD), and collagen volume fraction (CVF) was determined via Masson staining. RESULTS: The findings indicated that on Days 3, 7, and 14, Group D exhibited markedly superior incision healing compared to the other five groups. Conversely, Group M demonstrated inferior incision healing relative to the other groups. Microscopic examination revealed that Group D's enhanced function was attributed to improved tissue structure of incision neovascularization, characterized by larger vascular lumen diameters and more densely packed vascular endothelial cells. On Day 3, Group D showed significantly higher CD31 expression levels compared to the other five groups, while Group M exhibited notably lower CD31 expression. This trend persisted on Days 7 and 14, with Group D maintaining substantially higher CD31 expression. Similarly, on Day 3, Group D displayed significantly higher CD68 expression compared to the other groups, whereas Group M had significantly lower CD68 expression. This pattern was consistent on Days 7 and 14 as well. Additionally, Group D demonstrated significantly greater collagen fiber deposition on Days 3, 7, and 14, resulting in a significantly higher CVF compared to the other five groups. In contrast, Group M exhibited considerably lower CVF and reduced collagen fiber deposition. CONCLUSIONS: We hypothesized that the use of ropivacaine for incision subcutaneous infiltration anesthesia, in conjunction with dezocine and dexmedetomidine, may reduce pain stress and modulate the expression of inflammatory cytokines through the PI3Kγ/Akt signaling pathway and OGF-OGFr channel. This could lead to a reduction in IR production, inhibition of excessive inflammatory responses while preserving beneficial inflammatory reactions, upregulation of GM-CSF expression, increased fibroblast proliferation, stimulation of capillary proliferation, collagen fiber deposition, and macrophage aggregation, all of which contribute to improved wound healing.