Healing and histostructure of vascularized fasciocutaneous flaps under the conditions of brain tissue lyophilizate microinjections

Purpose To reveal a possible effect of subdermal injections of cerebrolysin on the parameters of healing and histomorphometric characteristics of the biological model of an extended fasciocutaneous flap with axial blood supply. Materials and methods A flap based on the superficial inferior epigastric artery (SIEA) and extended to the cranial side according to a template with an area of 18 cm2 was formed in 29 rats. After 90 minutes of femoral artery clipping, it was re-planted at the site of SIEA origination. After the operation, microinjections of cerebrolysin (0.1 ml) were performed subdermally. Four of them were injected in the mezhangiosomal zone in group Cer 1, and six were uniformly distributed over the area of the flap in group Cer 2. Comparison groups (Comp 1 and Comp 2) had injections of saline in similar number and zones. Negative control group had flaps without injections. Conditional normal sites were contralateral areas of the skin. Twelve days after the operation, the animals are euthanized. The methods of the study were computer planimetry, histomorphometry, and immunohistochemistry. Results In groups Cer 1 and Cer2, when compared with the negative control and placebo, relative areas of the epidermal defects associated with partial flap necrosis or delayed wound healing (2.15 % and 0.23 % vs. 13.72 % and 11.33 %, respectively) were reliably reduced. In Cer 1, hypovascularization of the hypodermis, thinning of the epidermis and dermis were noted. In Cer 2, compared with the control and Cer 1, the largest thickness and capillarity of the dermis and hypodermis were revealed, as well as the thickness of the epidermis and the numerical density of the skin appendages. Discussion The pronounced decrease in polymorphic cell infiltration of the dermis and hypodermis in the experimental groups indicates that the angiogenesis in the dermis stimulated by subdermal microinjections of cerebrolysin occurred by inhibition of inflammatory reactions and was caused by the direct action on endothelial cells. Conclusion To optimize the healing of fasciocutaneous flaps with axial blood supply in cases where their area exceeds the territory of the blood supplying artery, it is advisable to use microinjections of cerebrolysin uniformly distributed over the entire area of the flap, including its angiosomal and interangiosomal zones.