Application of physical, chemical-enzymatic, and combined methods for scanning electron microscopic study of internal...

To observe hidden internal cell-surfaces, previously described physical, chemical-enzymatic procedures and a newly developed combined method were applied to rat testes. With the physical method, it was very difficult to expose the masked cell-surfaces and cell damage tended to occur. Chemical and enzymatic methods used consisted of the hydrochloric acid(HCl) and collagenase technique for fixed tissue, and the collagenase-trypsin digestion technique for unfixed tissue. In the HCl and collagenase technique, the overall profiles of contractile cells and vascular smooth muscle cells were exposed, but basal profiles of germ cells and Sertoli cells were poorly exposed, whereas they were revealed more often with the double enzymatic digestion technique. However, the frequency of satisfactory exposure of the basal features was too low even with the latter technique. Our combined method was best for exposure of the basal features, and was also suitable for observing 3-dimensional profiles of germ cells and Sertoli cells.