Ů��С��Ƶ

It’s ovulation in the lab. A simulated female reproductive system behaves almost like the real thing over 28 days.

“Menstruation in a dish is one of my goals,” says of Northwestern University in Chicago. Kim works with organoids – small 3D clumps of tissue that behave more naturally than traditional, flat cell cultures. Linking different organoids together enables researchers to study complex organ systems in miniature, an approach that could lead to new insights and less animal testing.

Now Kim’s team has hooked up tissue from the ovaries, uterus, cervix and fallopian tubes, as well as the liver, which makes compounds that help to transport hormones.

The tissues responded to hormones made by the mini ovary: oestrogen in the first two weeks, then progesterone for the next two weeks. In the first half of the cycle, eggs grew and burst out of the ovary – mimicking ovulation. Tiny hairs in the fallopian tube began to beat faster, as if to waft the egg along, while cells in the uterus proliferated.

But the uterine cells didn’t die and break away during the progesterone phase, which normally triggers menstruation – probably because the uterine organoid had no blood vessels. Kim is now introducing these, but she hasn’t yet managed to get them to break down, which should prompt the uterine cells to die off.

If Kim’s team manages to complete the miniature menstrual cycle, it may lead to treatments for painful periods, fibroids and infertility.

“Having this functional axis between the ovaries and the other organs is what makes this so interesting,” says at the Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina. “In our body it’s not just the isolated organ that’s doing the work; you have these interactions with other organs.”

Read more: Mini-brains made from teeth help reveal what makes us sociable

This article will appear in print under the headline “Mini organs in a dish mimic menstrual cycle”