PROBLEM: To determine whether the expression of tumor necrosis factor (TNF-
alpha) correlates with TNF-alpha receptor expression in human endometrium.
METHOD OF STUDY: A multiprimer synthetic cDNA standard template containing
complimentary sequences for several cytokines including TNF-alpha and TNF-a
lpha receptor type 2 was constructed and used in quantitative reverse trans
cription polymerase chain reaction (Q-RT-PCR).
RESULTS: Endometrium from proliferative phase of the menstrual cycle expres
ses higher levels of TNF-alpha mRNA (2.35 +/- 0.2 x 10(5) copies/mu g of to
tal cellular RNA) than secretory phase ([1.3 +/- 0.08 x 10(5) copies] P < 0
.05), with a significant reduction during menses (1.2 +/- 0.1 x 10(4) copie
s) and postmenopausal period (8.1 +/- 1.6 x 10(4) copies [P < 0.051). In co
ntrast, TNF-alpha type 1 receptor mRNA expression was higher in endometrium
from the secretory phase (6.6 +/- 0.6 x 10(7) copies) compared to the mens
es (5.1 +/- 0.5 x 10(6) copies), proliferative phase (1.9 +/- 0.1 x 10(6) c
opies) and postmenopausal period (5.8 +/- 0.7 x 10(4) copies [P < 0.05]). C
omparatively, TNF-alpha receptor type 2 is expressed 10 to 100 fold higher
in the endometrium than TNF-alpha (P < 0.05).
CONCLUSION: The data confirm that human endometrium expresses TNF-alpha; an
d provide the first evidence that TNF-alpha expression is inversely related
to TNF-alpha type 1 receptor expression during the menstrual cycle. Such a
n inverse relation between TNF-alpha and TNF-alpha receptor expression may
provide a regulatory mechanism necessary to overcome the detrimental effect
of high levels of TNF-alpha on various endometrial cell types.