Figure 2.

Comparison of the cytoprotective effect of sulfite, H₂S, H₂S₂ and H₂S₃. WST‐8 values were shown for primary neuronal cultures 24 h after the addition of 1 mM glutamate (Glu) or without glutamate (−Glu) together with Na₂SO₃ (A), Na₂S (B), Na₂S₂ (C) and Na₂S₃ (D) (n = 8). *P < 0.05, as indicated; Student's t‐test. LDH values were shown for primary neuronal cultures 24 h after the addition of 1 mM glutamate (Glu) or no glutamate (−Glu) together with Na₂SO₃ (E), Na₂S (F), Na₂S₂ (G), and Na₂S₃ (H) (n = 8). Cytotoxicity [% = (Sample OD490 − low control/ (high control – low control) × 100 showed negative values at higher concentrations of Na₂SO₃, Na₂S, Na₂S₂, and Na₂S₃. Low control corresponds to untreated cells used to determine spontaneous LDH release. The negative cytotoxicity % values are caused by the values of samples being lower than the low control value. Even the spontaneous release of LDH was suppressed by Na₂SO₃, Na₂S, NaS₂, and Na₂S₃ possibly due to their cytoprotective effects on cells. All data shown are means ± SEM. In A‐D, *P < 0.05, significantly different as indicated; Tukey−Kramer test. In E‐H, ^# P < 0.05, significantly different as indicated, for values with glutamate. OD490, optical density at 490 nm.