Measuring the effects of postmortem time and age on mouse lens elasticity using atomic force microscopy

The mouse lens is frequently used both in vivo and ex vivo in ophthalmic research to model conditions affecting the human lens, such as presbyopia. The mouse lens has a delicate structure which is prone to damage and biomechanical changes both before and after extraction from the whole globe. When not properly controlled for, these changes can confound the biomechanical analysis of mouse lenses. In this study, atomic force microscopy microindentation was used to assess changes in the Young's Modulus of Elasticity of the mouse lens as a function of mouse age and postmortem time. Old mouse lenses measured immediately postmortem were significantly stiffer than young mouse lenses (p = 0.028). However, after 18 h of incubation, there was no measurable difference in lens stiffness between old and young mouse lenses (p = 0.997). This demonstrates the need for careful experimental control in experiments using the mouse lens, especially regarding postmortem time.

Automated summary

This study used atomic force microscopy microindentation to assess changes in the Young's Modulus of Elasticity of the mouse lens with age and postmortem time. It was found that immediately postmortem, old mouse lenses were significantly stiffer than young mouse lenses. However, after 18 hours of incubation, there was no measurable difference in lens stiffness between old and young mouse lenses, highlighting the importance of careful experimental control in studies involving postmortem time.