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

Occupational exposure limits for hazardous agents in the workplace—Part 1: Chemical hazardous agents (GBZ 2.1—2019) has been implemented since April 1, 2020. The document redefines the evaluation of occupational exposure by introducing a "reduction factor" to adjust the occupational exposure limits of chemical hazardous agents for long working hour systems to ensure a protection level reasonable for the workers and equivalent to conventional occupational exposure limits. This paper discussed common problems encountered in the context of using this adjustment strategy, such as the adjustment being unable to cover all working hours, and the adjustment of values of terms associated with occupational exposure limits. Corresponding solutions were proposed. Working cycle and average exposure time of each working cycle were introduced to evaluate the actual working hours of workers. Regarding involved terms, adjustments of their corresponding values were clarified according to their definitions and application scenarios. Examples were provided for occupational health service providers so that their occupational health practices could be carried out in a more scientific and reasonable manner.