為什么有些地方長(zhǎng)毛發(fā)有些地方卻不長(zhǎng)?

Why can millions of hairs grow from our heads, and yet our palms and the soles of our feet are as bare as anything? It all comes down to a special molecule in our bodies, according to the scientists who have found it.

為什么數(shù)以百萬計(jì)的頭發(fā)可以從我們的頭上長(zhǎng)出來，而我們的手掌和腳底卻是光禿禿的?據(jù)發(fā)現(xiàn)這一問題的科學(xué)家表示，一切都?xì)w結(jié)于我們體內(nèi)的一種特殊分子。

The hairless regions of our skin secrete a special type of molecule known as an inhibitor. This particular one is a protein named Dickkopf 2 (DKK2). These effectively brick-up the WNT pathway, which is in charge of triggering hair growth in our bodies.

我們皮膚的無毛區(qū)域分泌一種特殊的分子，稱為抑制劑。這種特殊的蛋白質(zhì)叫做Dickkopf 2(DKK2)。這些物質(zhì)有效地堵塞了WNT通路，而WNT通路負(fù)責(zé)刺激我們體內(nèi)的毛發(fā)生長(zhǎng)。

Scientists at the University of Pennsylvania School of Medicine believe certain animals have evolved to produce DKK2 in certain parts of their bodies, depending on what will best help different creatures to survive.

賓夕法尼亞大學(xué)醫(yī)學(xué)院的科學(xué)家們認(rèn)為，某些動(dòng)物已經(jīng)進(jìn)化到在身體的某些部位產(chǎn)生DKK2，這取決于哪種物質(zhì)最有助于不同的生物生存。

"In this study, we've shown the skin in hairless regions naturally produces an inhibitor that stops WNT from doing its job," Professor Sarah E. Millar, an author of the study published in the journal Cell Reports, commented.

這項(xiàng)研究的作者薩拉·E·米勒教授評(píng)論說：“在這項(xiàng)研究中，我們已經(jīng)表明，無毛區(qū)域的皮膚自然會(huì)產(chǎn)生一種阻止WNT發(fā)揮作用的抑制劑。”

Millar, who is a professor in dermatology at the University of Pennsylvania School of Medicine, continued: "We know that WNT signaling is critical for the development of hair follicles; blocking it causes hairless skin, and switching it on causes formation of more hair."

米勒是賓夕法尼亞大學(xué)醫(yī)學(xué)院皮膚學(xué)教授，他接著說：“我們知道WNT信號(hào)對(duì)毛囊的發(fā)育至關(guān)重要;阻斷它會(huì)導(dǎo)致無毛的皮膚，而開啟它會(huì)導(dǎo)致更多毛發(fā)的形成。”

For their study, the researchers analyzed mouse skin similar to that on a human wrist. Their work showed the protein DKK2 was expressed highly in this part of the mammal compared to hairy areas.

在他們的研究中，研究人員分析了老鼠與人類手腕相似的皮膚。他們的工作表明，與毛發(fā)區(qū)相比，這部分哺乳動(dòng)物體內(nèi)的DKK2蛋白表達(dá)量較高。

As with mice, humans don't grow hair in their wrist area, whereas other mammals, like rabbits and polar bears, do, the authors highlighted. When they compared DKK2 expression in mouse wrist skin with rabbit, they found it in lower levels in the latter.

研究人員強(qiáng)調(diào)，與老鼠一樣，人類手腕部位的毛發(fā)不會(huì)生長(zhǎng)，而兔子和北極熊等其他哺乳動(dòng)物會(huì)。他們將小鼠腕部皮膚的DKK2表達(dá)與兔腕部皮膚的DKK2表達(dá)進(jìn)行比較，發(fā)現(xiàn)兔腕部皮膚的DKK2表達(dá)較低。

"WNT is still present in hairless regions, it's just being blocked," explained Millar.

米勒解釋說：“WNT仍然存在于無毛地區(qū)，只是被阻擋了。”

The team hopes its findings could help prompt further research into hair growth. This could, in turn, lead to treatments in those where the body has stopped producing hair in particular areas, for instance those with deep wounds or burns, Millar said.

研究小組希望這一發(fā)現(xiàn)能有助于進(jìn)一步研究頭發(fā)的生長(zhǎng)。米勒稱，這進(jìn)而可能導(dǎo)致在身體某些特定部位停止長(zhǎng)頭發(fā)的人，比如那些有深度傷口或燒傷的人，得到治療。

"We hope that these lines of investigation will reveal new ways to improve wound healing and hair growth, and we plan to continue to pursue these goals moving forward," Millar said.

米勒表示：“我們希望這些研究將揭示改善傷口愈合和頭發(fā)生長(zhǎng)的新方法，我們計(jì)劃繼續(xù)追求這些目標(biāo)。”