The Effect of Three-Month Atorvastatin and α-Calcidol Administration on Some Bone Tissue Morphometric Parameters

Background.Osteoporosis is the fourth most common disease after cardiovascular diseases, cancer, and diabetes. All these diseases  have  common  pathogenetic  mechanisms  associated  with  impaired  cholesterol  metabolism.  In  recent  decades, the  use  of  the  key  enzyme  of  cholesterol  synthesis  inhibitors —  statins,  which  can  stimulate  osteogenesis,  has  become widespread. However, statins affect the production of the vitamin D active form by reducing the production of testosterone and thus reducing the activity of 1α-hydroxylase. The combined use of statins and α-calcidol (α-C) for the osteoporosis prevention  seems  promising. The  aim  of  the  study was  to  evaluate  the  effect  of  long-term  atorvastatin  (ATV)  and α-C administration on morphometric growth parameters and bone vascularization in the experiment.

Materials and Methods. The experiment was conducted for three months on 120 laboratory male rats, which were injected daily intragastrically with ATV and α-C. After 90 days of the experiment, the animals were decapitated under ether anesthesia. For the study, the right femur and jawbone were taken from the animals. The rat bone sections were impregnated with silver, decalcified, and the histosections were stained according to van Gieson. The distribution of the studied features was evaluated according to the Shapiro-Wilk test. The differences were considered statistically significant at p<0.05.

Results.It was found that ATV, both separately and together with α-C, increased the size of the newly formed bone in the endoostal and periosteal zones of the femur by 64.8; 40.4 and 15.8; 29.1%, respectively. The combined use of ATV and α-C had a positive effect on the growth of blood vessels in the femur (+23.4%). ATV increased the size of the newly formed bone from the periodontal and vestibular surfaces of the lower jaw by 18.3 and 29.5%, respectively. α-C potentiated the effect of ATV on the size of the newly formed bone tissue in the periodontal and vestibular growth zones of the mandibular bone by 10.1 and 15.0%, respectively. As for the number of vessels in the jawbone tissue, thanks to ATV, it increased by 17.2%, α-C had no effect.

Conclusion. ATV increases the thickness of the newly formed bone layer in the growth areas of the femur and jawbone and increases the number of vessels in the jawbone. α-calcidol increases the number of vessels in the bone tissue of the femur and potentiates the effect of ATV on the jawbone growth zones. The combined use of ATV and α-C shows that they positively complement each other.