Ma S, Cornford M E, Vahabnezhad I, Wei S, Li X
Departments of Obstetrics and Gynecology and Pathology, University of California, Los Angeles School of Medicine, Harbor-UCLA Medical Center, 1124 W. Carson Street, RB-1, Torrance, CA 90502, USA.
Brain Res. 2000 Feb 7;855(1):124-31. doi: 10.1016/s0006-8993(99)02379-3.
Neuronal nitric oxide synthase (nNOS) is induced in dorsal root ganglion neurons following axotomy in young rats, and is also increased in the gracile nucleus neurons of intact aged rats. The present study examined the influence of sciatic nerve axotomy on nNOS expression in the gracile nucleus in young compared to aged rats. The unilateral transection of the sciatic nerve was performed in young (4 months) and old (24 months) Fischer rats. Sections of rat medulla obtained 14 days after axotomy were immunolabelled using a polyclonal antibody directed against nNOS and stained by nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry, a marker of nNOS activity. In young rats, unilateral axotomy produced increased NADPHd containing neurons in the rostral region and the caudal region of the ipsilateral gracile nucleus compared to the side with intact sciatic nerve. In old rats, the NADPHd containing neurons in the ipsilateral gracile nucleus were moderately increased by axotomy over the age changes seen in the contralateral side. Similar results were obtained with nNOS immunoreactivity in young rats, but more cells were seen with NADPHd staining compared to nNOS immunostaining in old rats. The results suggest that unilateral sciatic axotomy causes an increase in nNOS expression in the ipsilateral gracile nucleus of young rats, which is still seen in old rats as an increase over normal aging changes.
在幼鼠中，轴突切断术后背根神经节神经元会诱导产生神经元型一氧化氮合酶（nNOS），而在未受损的老龄大鼠薄束核神经元中nNOS也会增加。本研究检测了与老龄大鼠相比，坐骨神经切断术对幼龄大鼠薄束核中nNOS表达的影响。对年轻（4个月）和老龄（24个月）的Fischer大鼠进行坐骨神经单侧横断。在轴突切断术后14天获取大鼠延髓切片，使用针对nNOS的多克隆抗体进行免疫标记，并用烟酰胺腺嘌呤二核苷酸磷酸黄递酶（NADPHd）组织化学染色，NADPHd是nNOS活性的标志物。在幼鼠中，与坐骨神经完整侧相比，单侧轴突切断术使同侧薄束核头侧区域和尾侧区域中含NADPHd的神经元增加。在老龄大鼠中，与对侧随年龄变化所见相比，轴突切断术使同侧薄束核中含NADPHd的神经元适度增加。在幼鼠中nNOS免疫反应性也得到了类似结果，但与老龄大鼠的nNOS免疫染色相比，NADPHd染色可见更多细胞。结果表明，单侧坐骨神经切断术会导致幼龄大鼠同侧薄束核中nNOS表达增加，在老龄大鼠中，这种增加表现为相对于正常衰老变化的增加。
