Which factor most commonly contributes to tissue autolysis in histology?

• A. Delayed fixation
• B. Immediate fixation
• C. Rapid processing
• D. Proper dehydration

Answer: (A)

Autolysis is the self-digestion of tissue by its own enzymes after the specimen is removed and before it is fixed. The most common contributor is delaying fixation. When tissue sits unfixed, intracellular enzymes, especially lysosomal enzymes, remain active and continue breaking down cellular proteins and membranes, degrading morphology and features you rely on for diagnosis. Fixatives like formalin rapidly penetrate tissue and cross-link proteins, effectively inactivating those enzymes and preserving structure. So, getting tissue into fixative promptly halts autolysis and maintains the architecture you need.

Immediate fixation would prevent autolysis by stopping enzymatic activity early. Rapid processing and proper dehydration are important for good histology overall and help minimize artifacts, but they do not drive autolysis themselves; the critical factor is the time before fixation.