Zhong-Fang Shi1, Li-Xin Xu1, Li-Ping Dong1, Xu Yan1, Shao-Hua Yang1, 2, Fang Yuan1*

Cultured astrocytes from Wistar rats are more susceptible to swelling induced by glutamate than those from Sprague-Dawley rats

Zhong-Fang Shi1, Li-Xin Xu1, Li-Ping Dong1, Xu Yan1, Shao-Hua Yang1, 2, Fang Yuan1*

1Department of Pathophysiology, Beijing Neurosurgical Institute, BeijingTiantanHospital, CapitalMedicalUniversity. Beijing, 100050.

2Department of Pharmacology and Neuroscience, University of NorthTexasHealthScienceCenter. Fort Worth, Texas76107-2699.

Corresponding author: Fang Yuan, Department of pathophysiology, Beijing Neurosurgical Institute, Capital Medical University, Tiantanxili 6, Dongcheng District, Beijing 100050, China. Tel: 86-10-67096750, E-mail: .

Abstract: Glutamate is one of the most important excitatory amino acids in the central nervous system, and plays important role in the formation and development ofbrain edema. Our previous studieshave found that glutamate induced astrocyte swelling and increasein aquaporin 4 (AQP4)expression in culture. Several studies have reported differences in the extent of ischemic lesion volumes existed among rat strains, but it is not clear whether cultured astrocytes from different rat strains have different response to glutamate.The aim of this study is to explore the difference between cultured astrocyte from Wistar rats and Sprague-Dawley rats after glutamate treament.Primary cultured astrocytes derived from the cerebral cortex of one-day-old Wistar or Sprague-Dawley rats. Subcultured astrocytes were treated with 0, 1 or 10 mMglutamate for 48 h. The viability of astrocytes was determined by LDH kits to assess the cellular injury, and the perimeter of astrocytes was measured by Image Pro Plus software after glial fibrillary acidic protein (GFAP) immunofluorescence staining to evaluate the astrocyte swelling.Then, the expression of AQP4in cultured astrocytes was detected by quantitative reverse transcription polymerase chain reaction. No difference was found in the LDH release after the treatment of 0, 1 or 10 mM glutamate in cultured astrocytes from these two strains, suggesting that glutamate had no effect on astrocytes viability in culture from different rat strains.The perimeter of astrocytes from Wistar rats was normally shorter than that from Sprague-Dawley rats, but was longer after the treatment of glutamate, suggesting that the change degree of astrocytes swelling induced by glutamate in Wistar rats was more significant than that from Sprague-Dawley rats. Meanwhile, AQP4 expression in Wistar rats was significantly higher than that from Sprague-Dawley rats after the incubation of 1 mM glutamate, suggesting that the change of AQP4 expression induced by glutamate in Wistar rats was more obvious than that from Sprague-Dawley rats. These results suggested that the change degrees of astrocytes swelling and AQP4 expression induced by glutamate in Wistar rats are more susceptible than those from Sprague-Dawley rats.

Key Words: glutamate; astrocyte; GFAP; LDH release, aquaporin 4.

Acknowledgments: This work was supported by the National Natural Science Foundation of China, No. 81271286 to Fang Yuan and No. 81228009 to Shao-Hua Yang.