Fifty male C57BL/6 mice provided by Hunan SJA Laboratory Animal Co., Ltd. (Changsha, China) resided in an animal house (temperature 26 ± 1 , humidity 50 ± 10%), in which the light was on for 12 h and off for 12 h. Mice were acclimatised for 1 week and allowed water and animal food with no limitations. Then, all mice were stochastically divided into 5 groups using random number tables available online (https://www.random-online.com/, accessed on 26 December 2021), including: (1) C group, a control group treated with normal saline for 7 consecutive days (n = 10); (2) M group, a model group with intraperitoneal injection of 20 mg/kg/day MPTP (Sigma-Aldrich, Taufkirchen, Germany, M0896) for 7 consecutive days (n = 10); (3) L group, treated with MPTP and 0.4 mg/kg/day liraglutide for 7 consecutive days (n = 10); (4) R group, treated with MPTP and 109 colony-forming unit (CFU) L. lactis MG1363 for 7 consecutive days via gavage (n = 10); (5) RG group, treated with MPTP and 109 CFUL. lactis MG1363-pMG36e-GLP-1 for 7 consecutive days via gavage (n = 10). All animals survived treatment and all animal experiments were administered from 9:00 to 12:00 in the morning to reduce systematic errors.

Fifty male C57BL/6 mice provided by Hunan SJA Laboratory Animal Co., Ltd. (Changsha, China) resided in an animal house (temperature 26 ± 1 , humidity 50 ± 10%), in which the light was on for 12 h and off for 12 h. Mice were acclimatised for 1 week and allowed water and animal food with no limitations. Then, all mice were stochastically divided into 5 groups using random number tables available online (https://www.random-online.com/, accessed on 26 December 2021), including: (1) C group, a control group treated with normal saline for 7 consecutive days (n = 10); (2) M group, a model group with intraperitoneal injection of 20 mg/kg/day MPTP (Sigma-Aldrich, Taufkirchen, Germany, M0896) for 7 consecutive days (n = 10); (3) L group, treated with MPTP and 0.4 mg/kg/day liraglutide for 7 consecutive days (n = 10); (4) R group, treated with MPTP and 109 colony-forming unit (CFU) L. lactis MG1363 for 7 consecutive days via gavage (n = 10); (5) RG group, treated with MPTP and 109 CFUL. lactis MG1363-pMG36e-GLP-1 for 7 consecutive days via gavage (n = 10). All animals survived treatment and all animal experiments were administered from 9:00 to 12:00 in the morning to reduce systematic errors.

Fifty male C57BL/6 mice provided by Hunan SJA Laboratory Animal Co., Ltd. (Changsha, China) resided in an animal house (temperature 26 ± 1 , humidity 50 ± 10%), in which the light was on for 12 h and off for 12 h. Mice were acclimatised for 1 week and allowed water and animal food with no limitations. Then, all mice were stochastically divided into 5 groups using random number tables available online (https://www.random-online.com/, accessed on 26 December 2021), including: (1) C group, a control group treated with normal saline for 7 consecutive days (n = 10); (2) M group, a model group with intraperitoneal injection of 20 mg/kg/day MPTP (Sigma-Aldrich, Taufkirchen, Germany, M0896) for 7 consecutive days (n = 10); (3) L group, treated with MPTP and 0.4 mg/kg/day liraglutide for 7 consecutive days (n = 10); (4) R group, treated with MPTP and 109 colony-forming unit (CFU) L. lactis MG1363 for 7 consecutive days via gavage (n = 10); (5) RG group, treated with MPTP and 109 CFUL. lactis MG1363-pMG36e-GLP-1 for 7 consecutive days via gavage (n = 10). All animals survived treatment and all animal experiments were administered from 9:00 to 12:00 in the morning to reduce systematic errors.