一氧化氮合成酶阳性神经元在大鼠下丘脑的分布及其衰老性变化

DISTRIBUTION AND AGE RELATED CHANGES OF NITRIC OXIDE SYNTHASE POSITIVE CELLS OF HYPOTHALAMUS IN THE RAT

实验用青年（2～3个月）、中年（15～18个月）和老年（26～30个月）三组Spe－ho大鼠，采用NADPH—D酶组织化学技术及计算机图像分析，研究了一氧化氮合成酶（NOS）阳性神经元在大鼠下丘脑的分布及其衰老性变化。结果发现NOS阳性神经元分布于室旁核、视上核、下丘脑外侧区、官窿周核及乳头体核；在正中隆起外侧带发现一些小阳性神经元；第三脑室室管膜上皮层内也含有阳性神经元。我们主要比较了阳性神经元相对密集的室旁核、视上核、下丘脑外侧区内阳性神经元的数量和平均截面积随年龄的变化。同青年组相比，中年组大鼠阳性神经元的数量和平均截面积没有显著性变化；但老年组大鼠阳性神经元的数量有不同程度的减少，减少率分别为室旁核15．95％．视上核15．16％，下丘脑外侧区21．26％（P＜0．05）；阳性神经元的平均截面积在室旁核、视上校增大（P＜0．05），而在下丘脑外侧区则减小（P＜0．05）。在老隼组大鼠下丘脑内，阳性神经元变稀疏，细胞形态发生了变化，有些细胞明显皱缩，细胞突起变细且扭曲等。结果提示NO可能参与了下丘脑激素的调节，在衰老过程中NOS神经元数量和形态的变化可能影响了NO的调节作用。

The present work studied the distribution and age related changeS of nitric oxide synthase positivecells of hyPothalamus in the rat with NADPH - diaphorase histochemical method and computer graphic analysissystem. Three groups of male rat were used: young age group (2～3 months, n = 6), Middle age group (15～18months, n = 6) and old age group (26～30 months, n = 6). The frozen sections (40 μm) of brain containing hypothalamus were stained for NADPH - diaphorase activity. NADPH - D peitive cells distributed in paraventricular nucleus (PVN), supraoptic nucleus (SON), fornical nucleus, lateral area of hyPOthalamus (HL), Periventricular nucleus and mammillary nuclei. In the lateral band of median eminence and ependyma of Ⅲ ventriculus positive cells also were found. The NADPH - D positive cells were distributed densely in PVN, SON, HL and werecounted (x ± sx ), and the area of each cell was measured (x ± sx ). The data was analysed with SAS statistic system. There were no significantly quantitative and morphological differences between the middle age group andsyoung age group (P>0. 05). In the old age group, NADPH-D positive cells in PVN, SON and HL reduced respectively by 15. 90 %, 15. 16 % and 21. 26 % (P<0. 05), and the area of positive cells in PVN and SON waslarger than that of the young and middle age groups, but the area of NADPH-D positive cells in HL was smallerthan that of the young and middle age groups (P < 0. 05 ). The results implicated that NO may be changed duringthe process of aging.