Neuroprotective Effect of Intravitreal Single-Dose Lithium Chloride after Optic Nerve Injury in Rats.

OBJECTIVE: Lithium is an old drug to control bipolar disorder. Moreover, it presents neuroprotective effects and supports neuronal plasticity. The aim of this study was to evaluate neuroprotective effect of intravitreal lithium after optic nerve injury. METHODS: Three dosages of lithium chloride, including 2 pmol, 200 pmol, and 2 nmol, were injected intravitreally after rat optic nerve injury. Proteins expression were assessed by western blot. Nitric oxide (NO) metabolites were measured by Griess test. Visual evoked potential (VEP) and optical coherence tomography (OCT) measurement were performed after trauma induction, in addition to H & E and TUJ1 staining of ganglion cells. RESULTS: Western blot depicted lithium can significantly increase antiapoptotic Bcl-2 protein level and reduce p-ERK, Toll-like receptor 4 (TLR4) and proapoptotic proteins such as Bax level in retinal tissue and Griess test reflected that NO metabolites level decreased in lithium treated eyes (P < .05). While, OCT showed no significant changes (P = .36 and P = .43 comparing treated group with trauma) in retinal ganglion cell layer thickness after lithium injection, VEP P2 wave amplitude increased significantly (P < .01) in lithium-treated eyes and its latency reduced (P < .05 for N1 wave and P < .01 for P2 wave). Tuj1 antibody-labeled retinal ganglion cells analyzing showed that the number of retinal ganglion cells were significantly higher in lithium treated eyes compared to untreated eyes with optic nerve injury. CONCLUSION: It seems intravitreally lithium has optic nerve neuroprotective effects by various mechanisms like overexpression of antiapoptotic proteins, suppressing proinflammatory molecules and proapoptotic factors, and decreasing nitric oxide.

Sodium Valproate Improves Skin Flap Survival via Gamma-Aminobutyric Acid and Histone Deacetylase Inhibitory System.

Sodium valproate interacts with biological systems through different mechanisms such as activation of gamma-aminobutyric acid (GABA)-sensitive chloride channels and inhibition of histone deacetylase. In this study, we examined the effect of sodium valproate in random-pattern skin flap of rats and investigated its mechanisms of action. Different types of experiments were carried out. In acute treatment, different doses of sodium valproate (50, 100, 150, 300 mg/kg) were injected intraperitoneally 1 h before surgery. In chronic treatment, the substance was injected each day for 2 wk. The size of skin necrosis was measured 1 wk after the surgery. The rate of secondary healing, amount of weight gain, hair growth, and wound regeneration were measured 2 wk after operation. In acute treatment, sodium valproate (100 mg/kg) reduced significantly the length of skin necrosis (P < 0.05). Administration of bicuculline (competitive antagonist of GABAA, 20 mg/kg) increased the length of skin necrosis (P < 0.05). In addition, administration of 100 mg/kg of sodium valproate and subeffective dose of bicuculline (10 mg/kg) prevented the protective effect of sodium valproate on skin flap necrosis (P < 0.05). In the chronically treated skin flap group, 100 mg/kg of sodium valproate reduced the length of necrosis (P < 0.01). Weight gain in the valproate group was more than that in the control group (P < 0.05). Skin also healed faster in the sodium valproate group than in the control group (P < 0.001). Combination therapy of sodium valproate and trichostatin A (330 nmol/kg) reversed the effect of valproate (P < 0.05). This study demonstrate that sodium valproate accelerates skin secondary healing in a rat model of skin flap probably through a GABA and histone deacetylase-dependent mechanism.