Objective To study the effect of glycine transporter 1 inhibitor M22 on epileptic sei-zures and cognitive dysfunction in epilepsy mice. Methods A total of 110 C57BL/6 mice were randomly divided into Normal control group (CON group,n=10),Model group (Mod group n=20),M22-1 group (n=20),M22-2 group (n=20),M22-3 group (n=20),M22-4 group ( n=20) according to weight. The chronic epileptic model was established by intraperitoneal injection of PTZ(30 mg/kg). The mice in CON group was injected with normal saline(10 mg/kg). The mice in Mod group were intraperitoneally injected with normal saline (10 ml/kg) and were injected with PT2 30 min later. The mice in M22-1 group,M22-2 group,M22-3 group,M22-4 group were intraperitoneally injected with M22 of corresponding dose(10 mg/kg,20 mg/kg,40 mg/kg,80 mg/kg)respectively,lasting for 2 weeks. Epilepsy seizures of mice in each group were recorded. The learning and memory function of epilepsy mice were evaluated by Morris water maze test . Then the mice were sacrificed and the apoptosis related proteins Bcl-2,Bax,Cyt-c in the cerebral cortex of mice were meas-ured by Western blot. Results (1)The mortality kindling rate,epileptic seizure grade and rate of tonic clo-nus in M22-2 and M22-3 group were significantly lower than those in Mod,M22-1 and M22-4 group( all P<0. 05). (2) In the directional navigation experiment,the escape latency of mice in each group decreased with time. On the 4th day,the escape latency of mice in M22-3 group was significantly shorter than that in Mod group,and the difference was statistically significant ((30. 24±9. 46),(16. 05±5. 72),t=20. 36,P<0. 05). In space exploration experiment,compared with Mod group,M22-3 group had more times of crossing platform ((6. 45±3. 62),(3. 23±2. 47),t=38. 63,P=0. 004) and longer time of target quadrant activity((21. 53± 6. 38) s,(11. 52±3. 15) s,t=37. 53,P<0. 05). (3)It was showed by Western blotting that the relative ex-pression levels of Bcl-2 in M22-3 group were significantly higher than those in Mod group(P<0. 05),while the Bax and Cyt-c in M22-3 group were significantly lower than those in Mod group(P<0. 05). There was no significant difference in Bcl-2, Bax and Cyt-c between M22-1 group, M22-4 group and model group ( P>0. 05). Conclusion M22 (40 mg/kg) has significant anti-epileptic effect and can effectively improve the cognitive dysfunction of epileptic mice,which may be related to the inhibition of neuronal apoptosis in mice.[Key words] Epilepsy; Glycine transporter 1 inhibitor; M22; Cognitive function; Pentyle-netetrazole

Background Lead and manganese are heavy metal pollutants widely existing in the environment, which can accumulate in the human body through the food chain, exert neurotoxicity, and cause neurodegenerative disorders. Especially in early childhood, the developing blood-brain barrier and nervous system are highly susceptible to environmental chemical pollutants. Most of the previous studies focused on the toxic effects of single heavy metal such as lead or manganese, while the studies on combined toxic effect are still scarce, and involved mechanisms are still unclear. c-Jun N-terminal kinase (JNK) is involved in neuronal development and regeneration, and some studies have found that JNK is involved in lead or manganese induced neurotoxicity. Its role in the toxicity of combined lead and manganese is unknown. Objective To understand the neurodevelopmental toxicity mechanism and to observe changes of JNK expression in zebrafish induced by combined lead and manganese exposure at environmentlly low concentrations. Methods Zebrafish embryos within 2 h post fertilization (hpf) were divided into four groups: control group, lead exposure group (0.1 mg·L⁻¹ lead acetate), manganese exposure group (0.3 mg·L⁻¹ manganous chloride), and lead-manganese combined exposure group (0.1 mg·L⁻¹ lead acetate +0.3 mg·L⁻¹ manganous chloride) and exposed to lead or/and manganese at designed levels for 7 d. Spontaneous movements and motor locomotion were observed, and mortality rate were calculated. The changes of JNK mRNA expression in zebrafish were evaluated. Results The experimental results showed that no significant effect of lead or/and manganese on spontaneous movements and mortality rate was found in zebrafish compared with the control group (P＞0.05). The results of locomotion analysis showed that compared with the control group, the activity counts and activity distance of zebrafish in the manganese exposure group were slightly increased (P＜0.01); the activity counts and activity distance of zebrafish in the lead exposure group were reduced by 50% and those in the lead-manganese exposure group were reduced by 80% (P＜0.01). Compared with the lead exposure group, the activity counts and activity distance of zebrafish in the lead-manganese combined exposure group decreased significantly by 60% (P＜0.05). The real-time quantitative PCR results showed that the JNK mRNA expression level was significantly increased in the lead-manganese combined exposure group compared with the control group(P＜0.01). Conclusion Lead exposure combined with manganese exposure at environmentlly low concentration can induce neurodevelopmental toxicity to zebrafish. JNK may be involved in neurodevelopmental toxicity induced by the combined exposure to lead and manganese.