Differential tissue shrinkage and compression in the z-axis: implications for optical disector counting in vibratome-, plastic- and cryosections.

The optical disector is among the most efficient cell counting methods, but its accuracy depends on an undistorted particle distribution in the z-axis of tissue sections. Because the optical disector samples particle densities exclusively in the center of sections, it is essential for unbiased estimates of particle numbers that differential shrinkage or compression (and resulting differences in particle densities along the z-axis) are known and corrected. Here we examined, quantified, and compared differential shrinkage and compression of vibratome-, celloidin- and cryosections.