| Abstract: | 本研究以眼科用Nd:YAG雷射對大白鼠施行虹膜(iris)的括約肌切斷術
(sphincterotomy)，使瞳孔放大，無光反應後，以光學顯微鏡及電子顯微
鏡觀察虹膜變化及其對睫狀神經節逆行性的影響。本實驗共用七隻大白鼠
，以右眼為實驗組，左眼為對照組。實驗組以Nd:YAG雷射破壞右眼縮瞳肌
後，飼養1、3、5、6、9、10、13 日時，經腹腔麻醉以灌流法犧牲。取下
左、右眼虹膜組織塊以臨界點乾燥法及金蒸著作掃描式電子顯微鏡之觀察
。並取出左、右眼的睫狀神經節及連著周圍的視神經等截成適當長度後，
脫水、包埋，以薄切分別用光學及穿透式電子顯微鏡觀察。實驗結果，對
照組方面：瞳孔以光照均有反應，虹膜組織以光學顯微鏡和掃描式電子顯
微鏡觀察無異常發現。而睫狀神經節以光學顯微鏡觀察，其分布可歸為兩
群：一在視神經髓鞘內，另則在髓鞘外。以穿透式電子顯微鏡觀察，其神
經元均無變化。實驗組方面：雷射術後第1 日起肉眼即可見瞳孔放大，無
光反應，在光學顯微鏡下觀察睫狀神經節其分布有兩群。掃描式電子顯微
鏡觀察虹膜變化，發現縮瞳肌斷裂處均可見裸露的海綿狀基質(stroma)，
而術後第1、3 日在斷裂組織上可見許多紅血球及巨噬細胞浸潤；術後第5
日則可看到纖維芽胞的觸手狀突起，推測乃組織修補期；雷射術後第10日
則可見瞳孔邊緣變平滑，無隆起現象。以穿透式電子顯微鏡觀察，在術後
第6 日開始，神經元的高爾基氏體開始膨大，術後第9 日高爾基氏體及內
質網均有顯著膨大變性。術後第13日除以上變化外，神經元細胞及核均有
皺縮現象。綜合以上觀察得知，經由雷射破壞虹膜括約肌可經由逆行性的
影響使睫狀體神經元退化，其細胞胞器如內質網、核醣體、高爾基氏體及
細胞核均有顯著變化，表示其神經傳導物質的正長製造功能受破壞。
In rats,laser sphincterotomy causes pupil dilatation
immediately. We studied the iris and ciliary ganglion responces
to Q-switched Nd:YAG laser that applicated to the iris in
anesthetized rats,and a little retrograde degeneration was
found on some ciliary ganglia. A total of 14 eyes of 7 Wistar
strain rats were examined. Seven right eyes of these rats that
received Nd:YAG sphincterotomy were grouped as experimental
ones, their intact left eyes were grouped as control ones. On
the 1st,3rd,5th,6th ,9th,10th,13th day after laser treatment,
the rats were sacrificed and their ciliary ganglia were
prepared for light and electron microscopic examination. In the
control group of our study, the light reflex of pupil remained
intact, the section of iris revealed 5 normal tissue layers
under light microscope and normal architecture under scanning
electron microscope.The ipsilateral ciliary ganglion of the
control group localized at 2 sites: one aggregated on the optic
nerve sheath,the other outside the optic nerve sheath. The
neurons of the ciliary ganglion are normal in morphology. In
the experimental group, the pupils dilated immediatelyaftwer
laser treatment and no prominent light responses in all 7 right
eyes. Under scanning electron microscopic observation,the pupil
margin became more smooth than the control group,loose stromal
tissue was found beneath the wound. Under transmission electron
microscopic examination of the ciliary ganglions,some
retrograde degeneration was noted from the 6th day,and became
more promunent on the 13th day. From our study, iris
sphincterotomy with Nd:YAG laser could induce retrograde
degeneration of the ipsilateral ciliary ganglion. |
