The effect of circadian RHYTHM on mcfarlane flap viability in rats

The Effect of Circadian Rhythm on McFarlane Flap Viability in Rats Introduction and objectives: Reactive oxygen radicals play an effective role in the pathophysiology of ischemia-reperfusion injury in flap surgery and the antioxidant-oxidant system in the organism shows endogenous circadian rhythm. In this study, we aimed to examine the effect of circadian rhythm change on flap viability in flap surgeries performed at different times during the day. Material and method: In the study, 32 Wistar Albino rats weighing 250-350 grams were used. Four groups were formed as morning, noon, evening and night groups, each containing 8 rats. The groups were operated every 6 hours at 06:00, 12:00, 18:00 and 24:00. A 9x3 cm McFarlane flap model was used in rats. At the end of 1 week, the study was terminated, photography was taken for topographic examination of the flaps and biopsy was performed from the flap for biochemical examination. Findings: When the percentage necrosis rates (Morning group (32.05%±12.25), noon group (36.20%±11.12), evening (38.32%±11.06) and night group (42.33%±16.65) ) were compared, no statistically significant difference was found (Χ2 (3) = 1.960; p = 0.581). When the serum melatonin, malondialdehyde, nitric oxide and glutathione levels and serum glutathione peroxidase and superoxide dismutase enzyme activities were compared between the groups, they showed circadian rhythm during the day, but this difference was not statistically significant (p> 0.05). When tissue nitric oxide levels were compared between groups, no statistically significant difference was found (p> 0.05). When tissue melatonin, malondialdehyde and glutathione levels and tissue glutathione peroxidase and superoxide dismutase enzyme activities were compared between the groups, they showed a significant circadian rhythm during the day and this difference was found to be statistically significant (p <0.05). Result: Our study examines the relationship between circadian rhythm change and flap survival. The changes in tissue oxidant and antioxidant levels during the day show a circadian rhythm and affect flap viability. Additional studies are needed to elucidate the relationship between circadian rhythm and flap surgery and the mechanism of flap chronosurgery.