Calretinin expression in hippocampus of mouse offspring from dams treated with β-hydroxy-β-methylbutyrate

Abstract

SummaryThe aim of the study was the immunohistochemical evaluation of calretinin (CR) expression in the hippocampus of neonatal (P0) and 21-day-old (P21) male mice from dams that received 0.2 g/kg b.w./day of β-hydroxy-β-methylbutyrate between the 26 th and 39 th day of pregnancy. The immunohistochemical peroxidaseantiperoxidase reaction was conducted on brain slices of offspring from control (C) and experimental (HMB) groups, using the specific antibody against CR. CR-immunopositive neurons of the hippocampal CA1 region and the dentate gyrus with the hilus were qualitatively and quantitatively assessed by means of an Olympus BX51 light microscope and the ImageJ 1.48v program. To demonstrate statistically significant differences, the Kruskal-Wallis test was used. The results of our studies revealed a decrease in CR expression intensity and the number of neurons only in the hilus of the dentate gyrus in both groups of mice (P0 and P21). The results indicate that HMB administration to pregnant dams may lead to damage or even loss of CR-immunopositive neurons in their offspring. This phenomenon may be related to calcium excess. Cells with CR expression inhibit the activity of other interneurons, causing a reverse of inhibition in principal neurons. The loss of cells with CR expression may interfere with the control and synchronisation of neuron excitability. In consequence, this may affect cognitive processes, memory and animal behaviour.