Investigating the effects of carvacrol in rats using oxygen-induced retinopathy model

Purpose: Investigating the effects of intraperitoneal carvacrol administration in rats using the oxygen-induced retinopathy (OIR) model. Methods: A total of 28 newborn Sprague Dawley rats were used and the OIR model was created using the 50/10% oxygen model. The study composed of four groups in total. While the OIR model was not used in Group I (control group), it was created for Groups II, III, and IV. About 0.01 mL carvacrol, bevacizumab, or 0.9% NaCl was administered intraperitoneal (IP) to the rats in all groups on postnatal day (PND) 14 as follows: Group I and Group II were administered 0.9% NaCl, Group III was administered bevacizumab, and Group IV was administered carvacrol. On PND 18, rats were sacrificed and their right eyes were enucleated. Results: Histopathological and immunohistochemical studies showed that the number of vascular endothelial cells (VECs), vascular endothelial growth factor (VEGF), and tumor necrosis factor-alpha (TNF-alpha) decreased similarly in Group III and Group IV compared with Group II. VECs values for Group I, Group II, Group III, and Group IV were measured as 0 +/- 0, 26.45 +/- 4.57, 7.75 +/- 1.98, and 5.78 +/- 1.72, respectively, and it differed significantly between groups (P < 0.001). Likewise, VEGF levels were observed as 0.06 +/- 0.01, 3.31 +/- 0.53, 2.47 +/- 0.44, and 2.49 +/- 0.52, respectively, and it differed significantly between groups (P < 0.001). TNF-alpha levels were recorded as 0.06 +/- 0.01, 3.58 +/- 0.38, 2.46 +/- 0.49, and 2.29 +/- 0.25, respectively, and it differed significantly between groups (P < 0.001). VECs, VEGF, and TNF-alpha were similar between Group III and IV (range of P values were 0.486-0.998). Conclusion: The study demonstrated that carvacrol significantly reduced retinal pathological angiogenesis, NV, VEC nuclei count, VEGF, and TNF-alpha levels. Moreover, the observed effects were comparable to those of bevacizumab.