Hippocampal metabolism of biogenic metals and selenium in patients with chronic manganese intoxication

BACKGROUND: The stability of trace element composition within the organism is crucial for maintaining the vital biochemical and biophysical processes. The severity of diseases associated with heavy metal accumulation is largely attributable to the irreversibility of this process and the persistent disturbances in metabolic systems. Therefore, investigating the imbalance of biogenic elements in patients with chronic heavy metal intoxication is highly relevant. AIM: The work aimed to determine the variations in the levels of biogenic metals and selenium in patients with chronic manganese chloride intoxication. METHODS: The experiments were conducted on 12 male white outbred rats weighing 180–220 g. The experimental group (n=6) received a 0.2% manganese chloride solution via automatic dispensers for 3 months, and the control group (n=6) was given tap water. The concentrations of manganese, copper, zinc, selenium, calcium, iron, and magnesium were measured in the left and right hippocampi using atomic emission spectroscopy with PerkinElmer Optima 7000 DV ICP-OES Spectrometer (USA). RESULTS: Based on the hippocampal content, the analyzed biogenic elements were arranged in the ascending order of concentration as follows: [Mn] [Cu] [Zn]=[Se] [Mg] [Fe] [Ca]. No evidence of asymmetry was observed in the levels of these metals and selenium across any of the animal groups. In rats that received the manganese solution, the hippocampal levels of manganese were more than twice as high compared to the control group (p 0.01). In the experimental group, the copper concentrations were found to be significantly higher (p 0.01), whereas the selenium levels were lower (p 0.01) compared to the control group. These effects demonstrated a bilateral pattern, affecting both the left and right hippocampi. The levels of iron, zinc, calcium, and magnesium remained unchanged. CONCLUSION: It can be hypothesized that the observed variations in biogenic elements may be responsible for the impairment of enzymatic systems, which include manganese, copper, and selenium.