Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 61 12 2024 08 22 728 735 EN Yasaman Kheirandish Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. AND Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. Mehrdad Panjnoush Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. Ehsan Babri School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. Ahmad Reza Dehpour Department of Pharmacology, Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran. 2024 02 10 2024 02 18 Statins affect the bone metabolism. Considering the role of nitric oxide (NO) in many physiological processes, this study assessed the effects of atorvastatin (ATOR) and NO on the mandible and skull bone density (BD) in ovariectomized rats. This study evaluated 48 female Sprague-Dawley rats in 6 groups (n=8). Groups 1 and 2 underwent sham surgery. Group 1 (sham) did not receive any medication, but group 2 (sham/ATOR) received atorvastatin. Groups 3 to 6 underwent ovariectomy. Group 3 (OVX) did not receive any medication, group 4 (OVX/ATOR) received atorvastatin, group 5 (OVX/L-NAME) received L-NG-nitro arginine methyl ester (L-NAME), and group 6 (OVX/ATOR/L-NAME) received both atorvastatin and L-NAME. Atorvastatin (40 mg/kg) was gavaged and L-NAME (3 mg/kg) was administered intraperitoneally for 4 weeks. All rats underwent lateral cephalometry before and after the interventions, and BD was measured at 2 points in the mandible and skull before and after the intervention by a digital densitometer. Data were analyzed by t-test, ANOVA, and Sidak test (alpha=0.05). The change in BD was 26.5±10.17 in the mandible and 22.17±9.45 in the skull in OVX group. These values were 25.63±5.55 and 28±8.59 in OVX/ATR, 1.5±7.78 and -1.88±4.39 in OVX/L-NAME, and 6.63±7.37 and 4.33±6.35 in OVX/ATOR/L-NAME, respectively. OVX/ATOR showed no significant difference (P=1), but OVX/L-NAME (P<0.001) and OVX/ATOR/L-NAME (P<0.001) groups showed significant differences with OVX group. The present findings indicated that atorvastatin had no significant effect on BD, but administration of L-NAME prevented osteoporosis in ovariectomized rats. https://acta.tums.ac.ir/index.php/acta/article/view/10966