N-Acetyl-L-cysteine in the Presence of Cu²⁺ Induces Oxidative Stress and Death of Granule Neurons in Dissociated Cultures of Rat Cerebellum

---

E. V. Stelmashook^1*, E. E. Genrikhs¹, M. R. Kapkaeva¹, E. A. Zelenova^1,2, and N. K. Isaev^1,2*

¹Research Center of Neurology, 125367 Moscow, Russia; E-mail: estelmash@mail.ru

²Lomonosov Moscow State University, Biological Faculty, Belozersky Institute of Physico-Chemical Biology, 119991 Moscow, Russia; E-mail: isaev@genebee.msu.ru

^* To whom correspondence should be addressed.

Received May 26, 2017; Revision received June 16, 2017

---

Addition into the culture medium of the antioxidant N-acetylcysteine (NAC, 1 mM) in the presence of Cu²⁺ (0.0005-0.001 mM) induced intensive death of cultured rat cerebellar granule neurons, which was significantly decreased by the zinc ion chelator TPEN (N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine). However, the combined action of NAC and Zn²⁺ did not induce destruction of the neurons. Measurement of the relative intracellular concentration of Zn²⁺ with the fluorescent probe FluoZin-3 AM or of free radical production using a CellROX Green showed that incubation of the culture for 4 h with Cu²⁺ and NAC induced an intensive increase in the fluorescence of CellROX Green but not of FluoZin-3. Probably, the protective effect of TPEN in this case could be mediated by its ability to chelate Cu²⁺. Incubation of cultures in a balanced salt solution in the presence of 0.01 mM Cu²⁺ caused neuronal death already after 1 h if the NAC concentration in the solution was within 0.005-0.05 mM. NAC at higher concentrations (0.1-1 mM) together with 0.01 mM Cu²⁺ did not cause the death of neurons. These data imply that the antioxidant NAC can be potentially harmful to neurons even in the presence of nanomolar concentrations of variable valence metals.

---

KEY WORDS: copper, cerebellar granule neurons, oxidative stress, N-acetylcysteine

DOI: 10.1134/S0006297917100108

---