Paclitaxel is effective for controlling astrocyte proliferation in vitro: Implications for generating ventral mesencephalic cultures enriched with dopamine neurons

Background: Primary embryonic ventral mesencephalic (VM) cultures are a high throughput tool for under-standing and manipulating dopamine neurons, to study the mechanisms that trigger their degeneration during Parkinson's disease (PD), and to test new drugs aimed at treating the disease. Unfortunately, primary cell cul-tures are often quickly overwhelmed by dividing astrocytes which both obscure neuronal cells and distort the cellular composition that exists in vivo. New method: To develop a new in vitro system whereby astrocyte division can be readily controlled while maintaining neuronal integrity, VM cultures were treated with different doses (1.75, 3.5, 7, 14 nM) of the anti-mitotic drug paclitaxel for up to seven days in vitro. The study subsequently sought to determine the importance of astrocytes in dopamine neuron survival when challenged with an exposure to the toxin 6-hydroxydopamine (6-OHDA). Results: Optical density (O.D.) measures of GFAP expression and counts of beta-III tubulin and tyrosine hydroxylase positive neurons reveals that a low dose of 3.5 nM of paclitaxel significantly reduced the density of GFAP + astrocytes in primary VM cultures, while maintaining the viability of neurons and dopamine neurons. Interest-ingly, a reduction of GFAP + astrocytes within primary VM cultures did not reveal any statistically significant differences in the number of dopamine neurons surviving treatment with 6-OHDA. Conclusions: These findings detail a quick and simple method for stabilising astrocyte numbers in primary VM cultures, without affecting the viability of dopamine neurons, and suggest that astrocytes may not enhance the survival of dopamine neurons when challenged with the 6-OHDA toxin. Background: Primary embryonic ventral mesencephalic (VM) cultures are a high throughput tool for understanding and manipulating dopamine neurons, to study the mechanisms that trigger their degeneration during Parkinson?s disease (PD), and to test new drugs aimed at treating the disease. Unfortunately, primary cell cultures are often quickly overwhelmed by dividing astrocytes which both obscure neuronal cells and distort the cellular composition that exists in vivo. New method: To develop a new in vitro system whereby astrocyte division can be readily controlled while maintaining neuronal integrity, VM cultures were treated with different doses (1.75, 3.5, 7, 14 nM) of the antimitotic drug paclitaxel for up to seven days in vitro. The study subsequently sought to determine the importance of astrocytes in dopamine neuron survival when challenged with an exposure to the toxin 6-hydroxydopamine (6-OHDA). Results: Optical density (O.D.) measures of GFAP expression and counts of ?-III tubulin and tyrosine hydroxylase positive neurons reveals that a low dose of 3.5 nM of paclitaxel significantly reduced the density of GFAP + astrocytes in primary VM cultures, while maintaining the viability of neurons and dopamine neurons. Interestingly, a reduction of GFAP + astrocytes within primary VM cultures did not reveal any statistically significant differences in the number of dopamine neurons surviving treatment with 6-OHDA. Conclusions: These findings detail a quick and simple method for stabilising astrocyte numbers in primary VM cultures, without affecting the viability of dopamine neurons, and suggest that astrocytes may not enhance the survival of dopamine neurons when challenged with the 6-OHDA toxin.

Automated summary

This research developed a new method for controlling astrocyte division in primary VM cultures by treating them with different doses of the anti-mitotic drug paclitaxel. The study found that reducing astrocyte density did not affect the survival of dopamine neurons when exposed to the toxin 6-OHDA. These findings suggest that astrocytes may not play a significant role in enhancing the survival of dopamine neurons under toxin challenge.