DEMONSTRATION OF EXTRACELLULAR ACID-PHOSPHATASE-ACTIVITY IN THE INVOLUTING, ANTIMESOMETRIAL DECIDUA IN FED AND ACUTELY FASTED MICE BY COMBINED CYTOCHEMISTRY AND ELECTRON-MICROSCOPY

An ultrastructural cytochemical study of acid phosphatase activity in the antimesometrial decidua on days 9-11 of pregnancy was performed in fed and acutely fasted mice. Specimens were fixed in a buffered mixtu re of paraformaldehyde and glutaraldehyde and were incubated in a buff ered medium containing sodium beta-glycerophosphate and cerium chlorid e for ultrastructural localization of acid phosphatase activity, Fed a nd fasted animals showed extracellular acid phosphatase reaction produ ct in the decidual-trophoblast interface, in the region of loosely and tightly packed, mature decidual cells, and in the region of predecidu al cells. Reaction product was absent in the region of nondecidualized stromal cells. Extracellular acid phosphatase activity was more consp icuous in the region of mature decidual cells in fasted mice than in f ed mice, and it was apparently similar in the region of predecidual ce lls in both fed and fasted mice. Acid phosphatase reaction product was also observed in lysosomes in all cells studied. Because acid phospha tase activity reflects the presence of lysosomal hydrolases in general , our results suggest that there is matrix degradation by lysosomal en zymes in both fed and fasted mice. These events may be part of the pro cess of tissue remodeling in regions of predecidual cells and mature d ecidual cells. However, it is also possible that, in the region of mat ure decidual cells, breakdown of matrix constituents is a mechanism to provide nutrients for the growing fetus. This mechanism is probably e nhanced in fasted mice. (C) 1998 Wiley-Liss, Inc.