Figure 2.

Isoflurane impairs the morphological transformation and cellular organization of cytoskeletal actin in cultured primary astroglia. (A) Immature astroglia at day-in-vitro (DIV) 4, immediately before treatment exhibit long, thin processes extending from one or both ends of their small cell bodies. (B, C) Sham-control astrocytes at DIV7 (B) and DIV10 (C) show progressive morphological changes indicative of maturation. At DIV7 they display fibroblast-like morphology with flat, polygonal cell bodies and short, stubby processes. By DIV10 their processes are longer and highly intermingled; intense growth results in the formation of a thick monolayer of cells. F-actin is arranged mainly in the actin stress fibers (ASFs). By DIV10 ASFs gradually become more densely organized in parallel stress fibers. (D, E) Isoflurane-treated astrocytes at DIV7 (D) and 10 (E) show delayed morphological transformation. At DIV7 they still display bipolar, spindle-like shape similar to their appearance in DIV4 cultures (A). Note the scarcity of cells compared to (B). By DIV10, the treated astrocytes still lag behind same-age sham control cultures and display morphological features similar to those in DIV7 sham controls (B). There is a lack of organized actin filaments bundles. In some cells, actin has started to reorganize into groups of filaments at the cell periphery, forming cortical actin (arrows). (A–E) Phalloidin staining, magnification: 10×. (F) Percentages of astroglia containing ASFs in DIV6 and DIV7 cultures treated on DIV 4. There were significantly fewer cells containing organized ASFs in treated vs. sham cultures. There was a 2-fold decrease in the percentage of astrocytes showing reorganization of cytoskeletal actin into ASFs at on DIV6 and DIV7 (*p < 0.05; n = 511–639 cells per data point; sampling done on 3 cultures per data point).