Reinholz M M, Haggard J J, Curran G L, Poduslo J F
Departments of Neurology and Biochemistry/Molecular Biology, Mayo Clinic and Foundation, Rochester, Minnesota, 55905, USA.
Exp Neurol. 1999 Sep;159(1):191-203. doi: 10.1006/exnr.1999.7117.
Free radical-mediated oxidative damage has been proposed to be an underlying mechanism in several neurodegenerative disorders. Previous investigations in our laboratory have shown that putrescine-modified catalase (PUT-CAT) has increased permeability at the blood-brain (BBB) and blood-nerve barriers with retained enzymatic activity after parenteral administration when compared to native catalase (CAT). The goals of the present study were to examine the plasma stability, spinal cord BBB permeability, nervous system biodistribution, and spinal cord enzyme activity of CAT and PUT-CAT after parenteral administration in the adult rat. TCA precipitation and chromatographic analyses revealed that CAT and PUT-CAT were found intact in the plasma and in the central nervous system (CNS) after iv, ip, or sc bolus injections. The highest percentages of intact CAT or PUT-CAT proteins were found in the plasma after iv administration, and similar percentages of intact CAT or PUT-CAT were found in the CNS following all three types of administration. Increases of 2.4- to 4.7-fold in permeability at the BBB and similar increases in the levels of intact PUT-CAT were found in different brain regions compared to the levels of CAT. A 2.4-fold higher level of intact PUT-CAT compared to that of CAT (P < 0.05) was found in the spinal cord 60 min after a sc bolus injection. CAT enzyme activity in the spinal cord was 50% higher (P < 0.05) in rats treated with PUT-CAT continuously for 1 week by subcutaneously implanted, osmotic pumps than the activity found in rats treated with PBS. These results provide evidence that intact, enzymatically active PUT-CAT is efficiently delivered to the nervous system following iv, ip, and sc administration and suggest that sc administration of PUT-CAT may be effective in treating neurodegenerative disorders in which the underlying mechanisms involve the action of free radicals and oxidative damage.
自由基介导的氧化损伤被认为是几种神经退行性疾病的潜在机制。我们实验室之前的研究表明，与天然过氧化氢酶（CAT）相比，腐胺修饰的过氧化氢酶（PUT-CAT）经肠胃外给药后，在血脑屏障（BBB）和血神经屏障处的通透性增加，且酶活性得以保留。本研究的目的是检查成年大鼠经肠胃外给药后CAT和PUT-CAT的血浆稳定性、脊髓BBB通透性、神经系统生物分布以及脊髓酶活性。三氯乙酸沉淀和色谱分析表明，静脉注射、腹腔注射或皮下推注后，在血浆和中枢神经系统（CNS）中发现CAT和PUT-CAT保持完整。静脉给药后，血浆中完整的CAT或PUT-CAT蛋白百分比最高，三种给药方式后，CNS中完整的CAT或PUT-CAT百分比相似。与CAT水平相比，不同脑区的BBB通透性增加了2.4至4.7倍，完整的PUT-CAT水平也有类似增加。皮下推注60分钟后，脊髓中完整的PUT-CAT水平比CAT高2.4倍（P < 0.05）。通过皮下植入渗透泵连续1周用PUT-CAT治疗的大鼠，其脊髓中的CAT酶活性比用PBS治疗的大鼠高50%（P < 0.05）。这些结果证明，静脉注射、腹腔注射和皮下注射后，完整的、具有酶活性的PUT-CAT能有效递送至神经系统，表明皮下注射PUT-CAT可能对治疗潜在机制涉及自由基作用和氧化损伤的神经退行性疾病有效。
