Ultrasonographic evaluation of L-name (n-nitro-l-argininemethyl ester hydrochloride) induced endothelial dysfunction in rat

Purpose In the rat model in which endothelial dysfunction (ED) was induced by N-Nitro-L- Arginine Methyl Ester Hydrochloride (L-NAME) administration, it was aimed to evaluate ED and atherosclerosis (AS) using ultrasonography (USG). Material and Method This study was carried out with 23 Wistar Albino (300-350 g) female rats. The rats were randomly assigned into four groups [control, sham, L-NAME early effect (EE), L-NAME late effect (GE)]. In the sham group, 0.5mL of 0.09% sodium chloride (SF) was administered intraperitoneally (IP) twice a day, for one week and the subjects was sacrificed on the 28th day. In the L-NAME groups; 0.5mL 185 μMol/kg L-NAME was administered IP twice a day for a week. EE and GE group rats were sacrificed on the 10th and 28th day of the experiment, respectively. Tissue and blood samples were evaluated by histopathological (HP) and immunohistochemistry (IHC) methods. Intima-media thickness (IMT) and right kidney resistive index (RI) values were measured at the beginning and at the end of the experiments. IMT evaluation were performed by USG in the right common carotid artery (CCA), left CCA, abdominal aorta (AA) and iliac artery (IA) of each rat. To confirm ED, endothelial nitric oxide synthase (eNOS), asymmetric dimethyl arginine (ADMA) and vascular endothelial growth factor (VEGF) levels were measured in plasma samples at the beginning and at the end of the experiment. eNOS and endothelin 1 (ET- 1) levels were measured at the end of the experiment in right CCA, left CCA, AA and right IA tissues to confirm development of ED. Also HP IMT measurements were performed at the end of the experiments for verification. Results In the EE group, statistically significant increase was found in the USG measurements of right CCA, left CCA, AA and IA IMT (p = 0.001, p = 0.001, p = 0.018, p = 0.008, respectively), compared to the sham group. In EE group, HP evaluation of IMT in the right CCA, left CCA, AA and IA also showed statistically significant increase, compared to the sham group (p=0,035, p=0,001, p=0,014, p=0,008, respectively). In the GE group, statistically significant increase was found in IMT measurements performd by USG in the right CCA, left CCA, AA and IA (p=0,001, p=0,001, p=0,003, p=0,001, respectively), incomparison to the sham group. In the GE group, statistically significant increase was found in the right CCA, left CCA, AA and IA IMT measurements performd by HP, compared to the sham group (p=0,008, p=0,005, p=0,005, p=0,008, respectively). In addition to these findings, renal RI increased significantly in GE group at the end of the experiment (p = 0.038). In the EE and GE groups, there was no statistically significant increase or decrease in serum eNOS, ADMA, VEGF levels and tissue eNOS and ET-1 levels at the beginning and end of the experiment (p> 0.05). Conclusion Our study has shown that USG, which is a practical and non-invasive method for imaging experimental animals, can be used quite effectively and consistently in the diagnosis and follow-up of ED and AS models induced by L-NAME administration. Our study has comprehensively confirmed the USG findings in the ED and AS models in the literature in different anatomical regions and revealed that there are USG measurement regions that will allow the experimental methods to be changed according to the disease and tissue destruction area to be modeled. In addition to the literature, we have showed that renal RI evaluation could also be used to evaluate ED and AS in rat models.