Local pharmacological preconditioning increases the survival of experimental skin flaps in rats

Angiogenic and anti-inflammatory properties of azadirachtin A improve random skin flap survival in rats

Random skin flaps are widely used to repair tissue defects. However, the distal flap regions are prone to ischemic necrosis, limiting clinical applications. Azadirachtin A, a fruit extract from the neem, improves tissue blood supply and metabolism, reduces cell swelling, promotes tissue healing, and prevents venous thrombosis. We explored whether it enhances random skin flap survival. Fifty-four Sprague-Dawley rats were divided into control, low-dose, and high-dose Azadirachtin A-treated groups using a random number table. We used an improved version of the McFarlane technique to create flaps. On day 2, superoxide dismutase and malondialdehyde levels were measured. Tissue slices prepared on day 7 were stained with hematoxylin and eosin. The expression levels of vascular endothelial growth factor (VEGF), toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-kB), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were immunohistochemically assayed. Microcirculatory blood flow was measured via laser Doppler blood flowmetry. Flap angiography was performed using the lead-oxide gelatin injection technique. And the azadirachtin A groups exhibited a greater mean flap survival area, an improved mean blood vessel density, a greater blood flow, and higher superoxide dismutase and VEGF levels, especially at the high dose. Azadirachtin A markedly reduced the levels of TNF-α, IL-6, IL-1β, TLR4, and NF-kB. These findings suggest that azadirachtin A promotes random skin flap survival by improving the blood supply, reducing tissue inflammation, and inhibiting flap ischemia reperfusion injury.

The Effect of Coenzyme Q10 (Ubiquinone) on Random Pattern Skin Flap Survival in Rat Model

BACKGROUND

In this study, the effect of coenzyme Q10 (CQ10) on flap survival was investigated.

METHODS

Fifty Wistar Albino rats were divided into 5 groups. The survival rates of the skin flaps were assessed 10 days after complete elevation of the flaps. Regions of survival and necrosis were drawn on transparent acetate sheets and scanned into a computer. Tissue samples were assessed histopathologically after staining with hematoxylin-eosin, vascular endothelial growth factor staining and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-Biotin Nick End-labeling staining. To evaluate the antioxidant effect of CQ10; malondialdehyde, nitric oxide levels were measured.

RESULTS

Viable flaps area was found higher in groups 3 and 4 as compared to groups 1, 2, and 5. In terms of vascular proliferation, elevated angiogenesis was observed in pathological specimens of groups 3 and 4 as compared to groups 1, 2, and 5. Malondialdehyde levels in groups 3 and 4 were found to be significantly decreased as compared to groups 1, 2 and 5 (P < 0.05). Moreover, serum levels of CQ10 were found significantly increased in groups 3 and 4 (P < 0.05).

CONCLUSIONS

In conclusion, CQ10 significantly improves flap viability in rat model, and the highest levels of serum CQ10 can be obtained by oral administration.

Investigation of reperfusion injury and ischemic preconditioning in microsurgery

Ischemia/reperfusion (I/R) is inevitable in many vascular and musculoskeletal traumas, diseases, free tissue transfers, and during time-consuming reconstructive surgeries in the extremities. Salvage of a prolonged ischemic extremity or flap still remains a challenge for the microvascular surgeon. One of the common complications after microsurgery is I/R-induced tissue death or I/R injury. Twenty years after the discovery, ischemic preconditioning has emerged as a powerful method for attenuating I/R injury in a variety of organs or tissues. However, its therapeutic expectations still need to be fulfilled. In this article, the author reviews some important experimental evidences of I/R injury and preconditioning-induced protection in the fields relevant to microsurgery.