Abstract
Introduction. The modern scientific medical literature contains numerous data on the peculiarities of structural transformation of bone tissue and the dynamics of its mineral composition in the age aspect, as well as under the influence of various exo- and endogenous factors. However, data on changes in the mineral component of bone tissue under conditions of long-term opioid exposure have not been identified in the available literature, although the widespread use of opioids in the clinic as drugs with analgesic effect makes this issue especially relevant.
The aim of our research was to study the dynamics of mineral composition of rat bone tissue with prolonged exposure to opioids.
Materials and methods. The study was carried out on 40 sexually mature outbred male rats with a body weight of 180-200 g and aged 3.5 months. Opioid addiction was modeled by the daily (once a day with identical intervals) injection of an opioid pain reliever nalbuphine. Nalbuphine was injected intramuscularly using to the following pattern: 1st week - 8 mg/kg, 2nd week - 15 mg/kg, 3rd week - 20 mg/kg, 4th week - 25 mg/kg, 5th week - 30 mg/kg, 6th week - 35 mg/kg. To determine the mineral composition of the bone tissue of rat's mandible, the method of atomic absorption spectral analysis (AASA) was used, which made it possible to detect eight mineral elements (calcium, phosphorus, magnesium, sodium, potassium, iron, strontium, zinc) in the studied samples. The concentration of researched elements in bone tissue samples was specified in mg/g. The research of mineral composition of the mandible was performed weekly in the span of 7 weeks of the experiment - 6 weeks of nalbuphine consumption, and then one week after its cessation (5 animals per each experiment period); 5 other animals were attributed to the control group.
Results. The results of this study allowed to determine the quantitative content of all investigated elements in the bone tissue at each stage of the experiment and indicate the presence of their expressed dynamics. Results of the atomic absorption spectral analysis of bone tissue of the rat's mandible body allowed to determine the quantitative content of four macro-elements (Ca, P, Mg, Na) and four microelements (K, Fe, Sr, Zn) and their specific shares in the mineral content of bone tissue in intact animals against the background of nalbuphine consumption and after its cessation. Against the background of nalbuphine consumption and after its cessation, specific shares of the studied macro-and microelements in the mineral component of bone tissue of the rat’s mandible have expressed dynamics - shares of calcium, iron, strontium, and zinc grow and remain higher than normal, and after nalbuphine is no longer administered, while specific shares of phosphorus, sodium, magnesium, and potassium are lower than in intact animals during seven weeks of the experiment. The dynamics of absolute indices of the researched mineral elements against the background of nalbuphine consumption and after its cessation differs from the dynamics of their specific shares. During six weeks of nalbuphine consumption, absolute levels of calcium, phosphorus, magnesium, sodium, zinc, and iron increase, remaining above the norm after its cessation; the amount of potassium decreases and remains lower than normal after nalbuphine withdrawal, while the amount of strontium decreases, though in the minimum, and after nalbuphine is no longer administered, it returns to the same value as in intact animals.
Conclusions. Results of the study allowed to determine the absolute quantitative content of all researched elements and their specific shares in the mandible bone tissue at each stage of the experiment and showed evident dynamics, which is different for each of the researched indices.