Scientists grow 'mini antlers' on mice, using deer stem cells

In August 2020, Chinese scientists grew deer antlers on the heads of mice. Paints a slightly disturbing picture, but as it turns out, deer antlers are one of the fastest-growing tissues in the Animal Kingdom, and thereby a closer look at its mechanisms could someday benefit regenerative medicine.

The deer appendages can grow as fast as 3/4 of an inch per day during the peak spring growing cycle and develop fully in just a few short months. Now, scientists at Northwestern Polytechnical University in Xi’an, China, have been researching the same and looking for ways to harness the instant growth rate of antler tissue by implanting stem cells from Sika deer antlers into the foreheads of lab mice, Field & Stream reported.

The result? Outlandish-looking rodents with "mini antlers", described by the journal Nature. The research was published in Science last month.

According to the paper, the results could be beneficial to heal bone injuries and regrowing lost limbs.

Deer antlers have an application in clinical bone repair

The Xi’an researchers examined the cellular make-up and gene expression dynamics of antler tissue during various stages of its growth. The stem cell populations that were highly capable of regenerative effects were then isolated and inserted into the heads of the test mice.

Interestingly, they found that shed antlers produced that were no more than five days old produced the most effective cell implants. These cells were grown from the base of the antler connecting to the skull plate, cultured in a petri dish, and then transplanted between the ears of hairless mice. The mice began to develop tiny antlers within 45 days of implantation.

The researchers hope to expand the capacity of modern medicine, Field & Stream wrote. "Our results suggest that deer have an application in clinical bone repair. Beyond that, the induction of human cells into [anlter-like] cells could be used in regenerative medicine for skeletal injuries or limb regeneration," the authors concluded.

Study Abstract:

The annual regrowth of deer antlers provides a valuable model for studying organ regeneration in mammals. We describe a single-cell atlas of antler regrowth. The earliest-stage antler initiators were mesenchymal cells that express the paired related homeobox 1 gene (PRRX1+ mesenchymal cells). We also identified a population of “antler blastema progenitor cells” (ABPCs) that developed from the PRRX1+ mesenchymal cells and directed the antler regeneration process. Cross-species comparisons identified ABPCs in several mammalian blastema. In vivo and in vitro ABPCs displayed strong self-renewal ability and could generate osteochondral lineage cells. Last, we observed a spatially well-structured pattern of cellular and gene expression in antler growth center during the peak growth stage, revealing the cellular mechanisms involved in rapid antler elongation.