[The permeability of the cell membrane in the human uterine smooth muscle at term pregnancy].
OBJECTIVE
To study the changes of the permeability of the uterine smooth muscle cell membrane at the various stages of labor, and comparing with the onset of labor.


METHODS
18 women (38 to 41 gestational weeks) were divided into three groups: late pregnancy not in labor, prelabor, active labor, and six cases in each group. The myometrium tissues in the corpus and lower segment of the uterus were studied by the Lanthanum tracing method under transmission electron microscopy (TEM).


RESULTS
Lanthanum entered into the smooth muscle cells, deposited in the mitochondria. The positive rates of the smooth muscle cells of lower segment by lanthanum tracing were markedly higher than that of corpus in late pregnancy group (P < 0.05), the difference were not found between lower segment and corpus in prelabor group (P > 0.05). The positive rates in corpus were significant higher than that of lower site in the active labor group (P < 0.05); Comparing corpus to corpus, the positive rates were not significantly different between late pregnancy and prelabor group (P > 0.05), then in active labor group it were markedly higher than those in the other two groups (P < 0.05, respectively); but in lower segment, the positive rates in late pregnancy group were significant higher than that in prelabor and active labor group (P < 0.05 respectively), no difference was found between prelabor and active labor (P > 0.05). The lanthanum deposition in the late pregnancy and prelabor groups was mainly showed in larger mitochondria within the smooth muscle cell while in active labor group, it laid on the outer and inner membrane and cristae of all the mitochondria.


CONCLUSIONS
The permeability of uterine smooth muscle cell membrane at term, pregnancy increases, especiany in uterine corpus, which showed a close correlation with the onset of labor.
Zhang
W
W
Xiang Ya Hospital of Hunan Medicial University, Changsha 410008.
Liu
J
J
Zeng
Q
Q
D000328:Adult; D002463:Cell Membrane Permeability; D005260:Female; D006801:Humans; D007745:Labor Onset / Q000378:metabolism*; D007811:Lanthanum / Q000493:pharmacokinetics; D009215:Myometrium / Q000378:metabolism* / Q000648:ultrastructure; D011247:Pregnancy
D007811:Lanthanum