Pau H, Hartwig H G, Fassbender R
Department of Ophthalmology, Heinrich Heine University, Düsseldorf, Germany.
Graefes Arch Clin Exp Ophthalmol. 1997 Oct;235(10):611-7. doi: 10.1007/BF00946936.
Homogenates of human clear lenses show an age-dependent reduction of enzyme activities. Topographical patterns of enzymes in clear and cataractous lenses can be visualized by histochemistry.
Human lenses were characterized by slit-lamp investigations as bearing different types of senile cataracts. Subsequently, lenses were removed by intracapsular extraction. Clear human lenses served as controls. Bovine lenses served to standardize freeze-cutting and incubation for lactate dehydrogenase histochemistry.
Bovine lenses show a sharp demarcation between the enzyme reaction of cortical fibers bearing cell nuclei and the non-reacting deeper fibers not exhibiting cell nuclei. Clear human lenses, lenses with deep supranuclear cortical cataracts, and lenses with nuclear cataracts exhibit the same borderline. However, in lenses with a subcapsular cortical cataract only the epithelium and a very thin layer of the most superficially located fibers show positive enzyme reactions.
In growing clear human and bovine lenses, independent of age, the more peripherally located cortical fibers bearing cell nuclei exhibit strong enzyme-histochemical reactions. More centrally located lens areas lacking cell nuclei increase in volume in an age-dependent manner. These lens regions do not exhibit enzyme activities detectable by our histochemical technique. Therefore the lens areas free of histochemical reaction product become larger with increasing age, whereas the peripherally located lens fibers apparently do not change their enzyme activities with age. Thus, homogenates of total lenses show age-dependent reductions of enzyme activities, although enzyme activities remain at a physiological level in cortical lens fibers with recognizable cell nuclei. In lenses with immature supranuclear cortical and (particularly) in lenses with black nuclear cataracts, cortical fibers still can exhibit high enzyme activities. Unexpectedly, also ruptured and broken fibers in immature deep supranuclear cortical cataracts show strong enzyme activities. In contrast, in lenses with (incipient) subcapsular cortical cataracts only the most superficially located lens fibers exhibit some enzyme activity.
人透明晶状体的匀浆显示酶活性随年龄增长而降低。透明晶状体和白内障晶状体中酶的拓扑模式可通过组织化学观察到。
通过裂隙灯检查对人晶状体进行特征描述，确定其患有不同类型的老年性白内障。随后，通过囊内摘除术取出晶状体。透明人晶状体作为对照。牛晶状体用于标准化乳酸脱氢酶组织化学的冷冻切片和孵育。
牛晶状体中，带有细胞核的皮质纤维的酶反应与无细胞核的深层纤维的无反应之间有明显界限。透明人晶状体、患有深层核上皮质性白内障的晶状体以及患有核性白内障的晶状体呈现相同的界限。然而，在患有囊下皮质性白内障的晶状体中，只有上皮细胞和最表层极薄一层纤维显示出阳性酶反应。
在生长中的透明人晶状体和牛晶状体中，与年龄无关，周边位置带有细胞核的皮质纤维呈现强烈的酶组织化学反应。缺乏细胞核的更靠中心的晶状体区域体积随年龄增长而增大。这些晶状体区域未显示出可通过我们的组织化学技术检测到的酶活性。因此，随着年龄增长，无组织化学反应产物的晶状体区域会变大，而周边位置的晶状体纤维的酶活性显然不会随年龄变化。因此，尽管带有可识别细胞核的晶状体皮质纤维中的酶活性保持在生理水平，但整个晶状体的匀浆显示酶活性随年龄增长而降低。在患有未成熟核上皮质性白内障的晶状体中，尤其是在患有黑色核性白内障的晶状体中，皮质纤维仍可呈现高酶活性。出乎意料的是，在未成熟深层核上皮质性白内障中破裂和断裂的纤维也显示出强烈的酶活性。相比之下，在患有（初期）囊下皮质性白内障的晶状体中，只有最表层的晶状体纤维呈现一些酶活性。
