Changes of Serum Concentrations of Alkaline Phosphatase and Metalloproteinase-9 in an Ovariectomized Wistar Rat Model of Osteoporosis

Osteoporosis is a systemic skeletal disease characterized by decreased bone mass, destruction of the microarchitectonics of bone structure and a high risk for fracture. One of the criteria for altered bone homeostasis includes the changes in serum levels of alkaline phosphatase (ALP) and the activity of matrix metalloproteinases (MMPs). The purpose of this study was to determine the serum concentrations of calcium (Ca²⁺), phosphorus (P), magnesium (Mg²⁺), alkaline phosphatase (ALP) and MMP-9 in ovariectomized rats. We used 35 female Wistar rats at reproductive age (2 months) divided into 2 groups: a control group (G1-SHAM) – 20 animals subjected to “false” ovariectomy and placebo-operation, and an ovariectomized group (G2-OVX) – 15 animals subjected to bilateral ovariectomy. Blood was collected from the abdominal aorta for testing levels of Ca^{2 +}, P, Mg²⁺, ALP and MMP-9. No statistically significant differences in serum concentrations of Ca²⁺, P and Mg²⁺ were found between G2 and G1 (p>0.05). The values of ALP and MMP-9 in rats of G2 were statistically significantly increased, as compared to G1 (p<0.05). The serum activity of ALP, which is a marker for bone formation, was increased in OVX-induced osteoporosis. Elevated serum MMP-9 levels in G2 confirmed the hypothesis that it is a marker for osteoclast activity.