兩棲類的表皮為一複雜之器官。表皮組織在生殖過程中可特化並作為育卵場所或營養來源等親代照顧之功能。艾氏樹蛙(Kurixalus eiffingeri)蝌蚪啄咬雌蛙泄殖腔附近的表皮時，會使雌蛙產下未受精卵給子代食用。本研究的目的是想了解艾氏樹蛙雌蛙表皮的結構並探討其功能，以同屬近緣種且無親代照顧的面天樹蛙(Kurixalus idiootocus)雌蛙做為對照的物種。其研究問題如下：1) 身體各部位(頭部、背部、腹部及泄殖腔)的表皮構造差異，2) 在繁殖與非繁殖季的泄殖腔表皮構造差異，3) 有和沒有撫育的泄殖腔表皮構造差異，4) 在繁殖和非繁殖季節的泄殖腔表皮泌乳激素受體強度差異。以組織學方法觀察表皮結構並量化表皮層厚度及細胞核質比，並且計算表皮層泌乳激素受體的染色強度。研究結果發現，艾氏樹蛙腹部表皮層厚度最厚，推測腹部是蛙類調節身體水分與滲透恆定的重要部位；而艾氏樹蛙在繁殖季中的泄殖腔表皮層厚度和細胞核質比是顯著大於非繁殖季的，推測表皮層厚度的增加是由於細胞的增生活躍。相反的，面天樹蛙雌蛙雖然在繁殖季表皮厚度也有增加，但細胞核質比沒有變化。我推論這兩種物種表皮的差異可能和蝌蚪的乞食行為有關。另外，泌乳激素受體的強度在艾氏樹蛙繁殖季節中顯著大於非繁殖季節，但是面天樹蛙則沒有不同；我認為艾氏樹蛙在繁殖季節中泌乳激素受體的強度的增加與雌蛙的親代照顧有關。許多研究已證實泌乳激素對於皮膚的生理過程扮演重要的角色，例如乳腺的發育和頭髮的生長；然而，泌乳激素是否參與艾氏樹蛙表皮的生理過程則需要更多的研究。 Amphibian integument is a complex organ and plays a special role in reproduction. Kurixalus eiffingeri tadpoles nip the females integument (mainly around cloaca), and female then lays unfertilized eggs to feed her tadpoles. The purpose of this study was to assess the structures and functions of K. eiffingeri female integument. I used Kurixalus idiootocus, a closed-related with no tadpole feeding behavior, as a control species. Specifically, I assessed 1) epidermic thickness among body regions (head, dorsal, ventral, and cloacal); 2) cloacal epidermis between breeding and non-breeding females; 3) cloacal epidermis between nesting and non-nesting females; 4) prolactin receptor (PRLR) intensity in cloacal epidermis between breeding and non-breeding females. I used a light microscopy to observe and measured the thickness, cell size, and nuclear-cytoplasmic ratio (N:C ratio) of epidermis layer. Then I calculated the staining intensity of prolactin receptor (PRLR) in epidermis. Results showed that the epidermic thickness varied among body regions, and the ventral epidermis was the thickest and probably responsible for osmoregulation. Cloacal epidermal thickness and NC ratio of K. eiffingeri in breeding season are significantly higher than that of non-breeding season, indicating high levels of cell proliferation. On the contrary, K. idiootocus epidermis increased in thickness during breeding season but not in NC ratio. The difference in epidermic structures may relate to the egg-feeding behavior of female frogs. The PRLR intensities between breeding and non-breeding K. eiffingeri females were significantly different but not in K. idiootocus. I contend that PRLR intensity increased in breeding K. eiffingeri may associate with maternal behavior of female frogs. Prolactin has been demonstrated to have importance effect on the physiological processes of skin, such as mammary glands development and hair growth, however, whether prolactin involves in physiological process of epidermis in K. eiffingeri needs further studies.
