The Expression Of Pancreatic Triglyceride Lipase In Injured Primary Type 1 And Type 2 Astrocytes

Astrocytes are glial cells, which are the largest in numbers and widely distributed in central nervous system (CNS). According to the theory of astrocytes lineages, astrocytes can be divided into two types:type 1 astrocytes(T1A) and type 2 astrocytes (T2A). T1A express connexin 43 regulating gap junctions and MHCII and participate in inducing the formation of blood brain barrier and neuroimmuntity. T2A can synthesize chondroitic acid, accumulate GABA neurotransmitters, participate in regulating ecto-neurotransmitters and encircle with nodes of Ranvier to contributing to maintaining the formation or functions of nodes of Ranvier and myelin in CNS. Gene expression profile analysis showed that the expression of PTL in T1A and T2A were significant which suggested PTL may play a role in different mechanisms in the two types of astrocytes. Therefore, Understanding the role of PTL in the regeneration and repair following CNS injured would be helpful for the treatment of CNS injury to provide new ideas and methods.Objective To establish the two types of astrocytes injury model in vitro, detect the expression of PTL following astrocytes injury and explore the role of PTL in the repair and regeneration of central nervous system after mechanical injury.Methods Based on the different properties of developmental time-course and cellular adhesions, type 1 astrocytes and type 2 astrocytes were separated and purified by mechanical shaking and differential adhesion method. Immunofluorescence double labeling identified the two types of astrocytes and detected the expression of PTL in T1As and T2As. Established astrocytes mechanical injury model, the expression of PTL in injured astrocytes from 6h,12h,24h,48h and normal astrocytes were observed and examined by Real-time PCR and Western blot assay. Chitosan in different concentrations were added in the two types of astrocytes when the expression of PTL was the highest after astrocytes injury. The expression of PTL was detected by Western blot when injured anstrocytes were dealt with chitosan after 24 hours.Results Type 1 astrocytes and type 2 astrocytes were successfully isolated by mechanical shaking and differential adhesion method. Immunofluorescence double labeling showed that PTL were widely distributed in nucleus, cytoplasm and cellular processes in T2A whereas expressed weakly only in the nucleus in T1A. Real-time PCR and Western blot indicated that the expression of PTL both in the level of mRNA and protein began to increase after mechanical injury of astrocytes at 6h and reached the peak at 24h, compared with the control group difference was significant (P<0.01), and then declined. Wherares, the expression in T2A was deeply higher than in T1A. When astrocytes were dealt with different concentrations of chitosan at 24h after injury, the expression level of PTL increased in low concentration of chitosan, and decreased as the concentrations of chitosan increased.Conclusions (1) The expression of PTL increased after mechanical injury in T1A and T2A, which indicated that PTL may be closely associated with CNS regeneration and repair after injury. (2) The expression of PTL was significantly higher in normal and injured T2A than that in T1A, which suggest that T2A play an important role in lipid metabolism and the process of myelin regeneration after CNS injury. (3) Chitosan of low concentration can increase the expression of PTL in T1A and T2A after injury, which indicated that chitosan can regulated the lipid metabolism on the process of repair and regeneration after CNS injury.