Ahsan Ullah¹, Fatimah A. Al-Saeed², Alduwish Manal Abduallah³, Ahmed Ezzat Ahmed^4,5, Asim Shahzad¹, Nouman Amjad¹, Arooj Ali⁶, Mohamed S. Mostafa⁷ and Riaz Hussain^1*

Calcium nanoparticles (Ca-NPs) are emerging as promising materials and are frequently used in different areas of medical science including treatment therapy. In current study, different unwanted impacts of Ca-NPs were observed on various tissues including teeth, testes, brain and erythrocytes of male albino rats. A total of twelve active and sexually mature albino rats free from any obvious clinical ailments were procured from local market and were placed in wire cages in three groups. The rats in groups B and C were administered Ca-NPs at two dosage levels (25 and 50 mg/kg body weight) while the rats in control group received no treatments. No physical changes in terms of mortality, morbidity, behavioral and neurological signs were observed in rats of all groups. Different pathophysiological alterations such as significantly increased contents of oxidative parameters (reactive oxygen species and thiobarbituric acid reactive substance) while reduced contents of antioxidant enzymes (reduced glutathione, peroxidase, catalase and superoxide) in red blood cells (RBC) of albino rats of group B and group C were recorded. Results on various histo-architecture changes in different visceral organs like the testes, brain, and teeth exhibited various microscopic alterations in albino rats treated with high dosages of Ca-NPs as compared to the control group. Therefore, the current study showed that the prepared Ca-NPs had adverse physiological effects on different tissues in the albino rats.