The influence of acelysin and nimotop on the cellular response of the hippocampus during the dynamics of experimental subarachnoid hemorrhage

Abstract

Aim. Immunohistochemical study of rat hippocampal neurons and astrocytes at different time-points of experimental brain hemorrhage treated with acelysin and nimotop. Materials and methods. Subarachnoid hemorrhage (SAH) was modeled according to R. V. Dudhani et al. using 35 Wistar rats which were divided into 7 groups. Animals of the 1st and 2nd groups, for 4 and 7 days respectively received acelysin at a dose of 15 mg/kg once a day; animals of the 3rd and 4th groups received nimodipine at a dose of 0.3 mg/kg every 8 hours for 4 and 7 days. In groups 5th and 6th (control), SAH was modeled without treatment with observation periods of 4 and 7 days, respectively. The 7th group consisted of intact animals. Hippocampal CA1 fields were studied immunohistochemically evaluating the expression of CASP3, NeuN, GFAP by the relative area of immunostaining in ImageJ. Results. CASP3 expression in hippocampal neurons increases by 2.3 and 5.7 times on day 4 and by 1.8 and 3.9 times on day 7 of experimental SAH (groups 1–4) compared to intact group. GFAP expression increases in all observation groups compared to intact animals with the maximum values in the 5th group – by 8.14 times. The dynamics of NeuN expression in hippocampal neurons when using acelysin and nimotop corresponds to the inverse dynamics of CASP3 expression. The NeuN expression increases maximally on the 7th day of acelysin use and is equal to 91.76 % of the intact group values. Conclusions. The experimental SAH is accompanied by a change in the expression of CASP3, NeuN in neurons and GFAP in astrocytes. The use of acelysin and nimotop leads to decrease in CASP3 expression in hippocampal neurons on the 4th day by 3.82 and 1.54 times compared to control group, and on the 7th day by 4.00 and 1.84 times, respectively, which reflects the positive effect of the therapy on the prevention of apoptotic death of hippocampal neurons. Compared with nimotop, the use of acelicine significantly increases the expression of NeuN on day 4 and 7 – by 1.84 and 1.95 times, respectively, which indicates a more pronounced neuroprotective effect of acelysin on hippocampal neurons in SAH. Increased GFAP expression reflects the dynamic reactive remodeling of astrocytes, while the use of acelysin and nimotop does not affect the reduction of GFAP levels on days 4 and 7 of SAH and their return to baseline values. The results of the present experimental study provide a theoretical justification of the feasibility of including metabolitotropic drugs in the basic therapy of SAH.