Effects of Cerebral Ischemia on Levels of Vascular Endothelial Growth Factor (VEGF) and Its Soluble Receptors: A Possible Link to Angiogenesis in Arteriovenous Malformations.

AIM: To investigate the levels of vascular endothelial growth factor (VEGF) in the brain, and its soluble forms, namely sVEGFR1 and sVEGFR2, levels in the plasma of rats after cerebral ischemia. MATERIAL AND METHODS: Rats were divided into three groups as follows: Group 1: Sham-operated group, Group 2: Complete occlusion of the right carotid artery, Group 3: Complete occlusion of the right carotid artery and temporary occlusion of the left carotid artery for 10 min. Blood samples were collected on days 0 and 10 prior to the sacrification to measure the sVEGFR1 and sVEGFR2 levels. On day 10, animals were sacrificed, and brain tissue was collected to analyze VEGF expression. RESULTS: Postoperative sVEGFR1 levels reduced significantly in Group 3, while it remained stable in other groups. sVEGFR2 levels did not change in any group. Although VEGF staining scores in the groups that underwent ischemia procedures increased compared to group 1, no significant differences were observed. CONCLUSION: Decreased levels of sVEGFR1 can be a mechanism contributing to angiogenesis in arteriovenous malformations by increasing the levels of VEGF available to bind membrane-bound VEGFRs.

Comparison of TachoComb and TissuDura in Terms of Adverse Effects and Complications in Duraplasty in Rats.

AIM: To compare two synthetic graft materials, TachoComb®, a fibrin sealant composed of collagen, fibrinogen, thrombin and aprotinin and TissuDura®, a collagen-based biomatrix. MATERIAL AND METHODS: Thirty Sprague?Dawley rats were randomly divided into three groups with 10 animals in each group. A dural defect was created on the left parietal bone of each animal, and the dural defect was repaired using either TachoComb® (TachoComb group) or TissuDura® (TissuDura group). Sham animals did not receive any dural graft. After 21 days of follow-up, the brain was dissected, and inflammation, oedema, gliosis and foreign body reaction in the bone and parenchymal tissue were investigated histopathologically. RESULTS: The TachoComb group showed significantly greater inflammation, gliosis and parenchymal foreign body reaction compared with the sham group. By contrast, the TissuDura group had significantly lower gliosis and insignificantly less inflammation in the bone and parenchymal foreign body reaction compared with the TachoComb group. CONCLUSION: In conclusion, our results suggest that TissuDura® may be considered more biocompatible than TachoComb® in duraplasty.

Stereological and histopathological evaluation of the effect of Thymoquinone on peridural fibrosis following laminectomy in rats

Background/aim: This study's aim was to investigate the effects of thymoquinone, which is the essential bioactive component of the volatile oil of Nigella sativa on the peridural fibrosis in rats following laminectomy. Materials and methods: Twenty female Wistar Albino rats were used in our study. The rats were randomly divided into 2 groups: Sham and Surgery + Thymoquinone. Both groups underwent laminectomy at L1 under general anesthesia. The Sham group was not subjected to any drug application. The 2nd group was treated with intraperitoneal 10-mg/kg thymoquinone once per day for a period of 28 days, following the same surgical procedure. All of the group specimens were sacrificed after 4 weeks, and the laminectomy area was examined in terms of new bone volume, capillary volume, and fibrosis volume using stereological approaches. Results: Statistically significant differences were found between the Sham and Surgery + Thymoquinone groups in terms of new bone volume (P = 0.01), capillary volume (P = 0.01), and fibrosis volume (P < 0.001). It was noted that Thymoquinone caused a significant increase in new bone volume, vascular volume and, a significant decrease in fibrosis volume. Conclusion: The results of our study indicate that thymoquinone is effective in decreasing peridural fibrosis when applied to a laminectomy model.