Graduate School of Engineering and Science, University of the Ryukyus, Motobu, Okinawa, 905-0227, Japan.
Fish Physiol Biochem. 2013 Feb;39(1):47-51. doi: 10.1007/s10695-012-9632-2. Epub 2012 Mar 16.
The three-spot wrasse (Halichoeres trimaculatus), which inhabits the coral reefs of Okinawa, changes sex from female to male. Sex change in this species is controlled by a social system. Oocytes disappear completely from the ovary, and male germ cells and somatic cells comprising testicular tissue arise a new during the sex change process. However, little is known of the fate and origin of the gonadal tissue-forming cells during sex change. In particular, the fate of ovarian somatic cells has not been determined, although the ovarian tissue regresses histologically. To approach this question, we analyzed apoptosis and cell proliferation in the sex-changing gonads. Unexpectedly, we found that few apoptotic somatic cells were present during sex change, suggesting that ovarian somatic cells might survive during the regression of the ovarian tissue. On the other hand, cell proliferation was detected in many granulosa cells surrounding the degenerating oocytes, a few epithelial cells covering ovigerous lamella and a few somatic cells associated with gonial germ cells at an early stage of sex change. Then, we found that proliferative ovarian somatic cells remained in the gonads late in the sex change process. Based on these results, we concluded that some functional somatic cells of the ovary are reused as testicular somatic cells during the gonadal sex change in the three-spot wrasse.
三斑鹦鲷（Halichoeres trimaculatus）栖息在冲绳的珊瑚礁中，会从雌性转变为雄性。这种物种的性别转变受社会系统控制。在性别转变过程中，卵母细胞会从卵巢中完全消失，而包含睾丸组织的雄性生殖细胞和体细胞会重新出现。然而，对于在性别转变过程中性腺组织形成细胞的命运和来源，人们知之甚少。特别是，虽然卵巢组织在组织学上退化，但卵巢体细胞的命运尚未确定。为了解决这个问题，我们分析了正在进行性别转变的性腺中的细胞凋亡和细胞增殖。出乎意料的是，我们发现性别转变过程中很少有凋亡的体细胞，这表明卵巢体细胞在卵巢组织退化过程中可能存活下来。另一方面，在正在退化的卵母细胞周围的颗粒细胞、覆盖产卵板的少数上皮细胞和与精原生殖细胞早期相关的少数体细胞中检测到细胞增殖。然后，我们发现增殖的卵巢体细胞在性别转变过程的后期仍存在于性腺中。基于这些结果，我们得出结论，一些卵巢的功能性体细胞在三斑鹦鲷的性腺性别转变中被重新用作睾丸体细胞。
