Objective: To investigate the postnatal development of perineuronal net (PNN), Nogo receptor (Nogo R) in visual development and the effect of fluoxetine(Flx) on remodeling it in the visual cortex of adult rats. Methods: Experimental study. (1) Wistar rats were divided into postnatal weeks (PW)1,PW3,PW5,PW7,PW9 group (8 rats in each group) according to the age of PW. The changes of PNN and Nogo R were observed in the visual cortex of each group. (2) The adult rats (10 weeks after birth) were randomized into Flx 0W, Flx 2W, Flx 4W, Flx 6W and Flx 8W group (8 rats in each group) according to Flx administrational weeks. The influence of Flx on the expression of PNN and Nogo receptor in the visual cortex was detected by immunofluorescence and western blots. (3) The adult rats were randomized into Cont (negative control), Flx, binocular form deprivation(BFD,positive control) and BFD+Flx group (8 rats in each group). Flx group accepted oral administration at the dosage of 0.2 mg/ml once per day for 4 weeks. The eyelids were binocularly sutured for 2 weeks to form the BFD group, and the combination of Flx administration and BFD was performed in the BFD+Flx group.No intervention was conducted in the control group (Cont group). Immunofluorescence was used to observe the expression pattern of PNN staining by biotinylated wisteria floribunda lectin (WFA). The expression of Nogo R in the visual cortex was detected by immunofluorescence and Western blots. The expression of PNN and Nogo R were examined in each group. And t test, analysis of variance and rank sum test were employed for inter-group comparison based on the homogeneity of variance. Bonferroni method was used for multiple comparison and simple linear regression analysis was used for the trend. Results: (1) The expression of PNN (standardized b=0.97, P=0.005) and Nogo R (standardized b=0.96, P=0.010) increased during the postnatal development and the Nogo R reached the matured level at PW7 (PW7 vs. PW9, 131.83±3.78 vs. 135.11±3.92, Z=1.93, P=0.062). (2) Flx significantly decreased PNN in the visual cortex of adult rats. The density of PNN-positive cells in the visual cortex of healthy adult rats fed with Flx for 4 weeks was (86.22±7.68)/mm(2), which was similar to that of 3 weeks old rats [(84.21±6.68)/mm(2), t=2.08, P=0.073]. The expression of PNN (standardized b=-0.88, P=0.040) and it's receptor Nogo R (standardized b=-0.90, P=0.007) decreased with prolongation of Flx use. (3) The expression of Nogo R (t=13.42,11.47, 18.13; P=0.012, 0.013, 0.001; Flx, BFD and BFD+Flx group vs. Cont group) and the density of PNN (t=10.09, 7.64, 13.01; P=0.007, 0.011, 0.001; Flx, BFD and BFD+Flx group vs. Cont group) could be modulated by Flx and BFD after the critical period. There are no differences in BFD and Flx group on Nogo R changes (t=2.41, P=0.153). The expression of Nogo R protein was also different among the 4 groups (H=5.69, P=0.041). The effect of Flx combined with BFD was better than the Flx or BFD alone (Flx vs. BFD+Flx, Z=4.22, P=0.005; BFD vs. BFD+Flx, Z=3.09, P=0.010). Conclusions: The expression of PNN and Nogo R increase during the postnatal development. Chronic Flx treatment decrease the expression of PNN and Nogo R after the critical period in the visual cortex of adult rats, that is the same as BFD. (Chin J Ophthalmol, 2019, 55:37-45).
目的： 探讨视皮层神经元周围网（PNN）及Nogo受体在大鼠视觉发育过程中的变化及氟西汀对成年大鼠视皮层PNN及Nogo受体的影响。 方法： 实验研究。（1）按出生后周龄（1、3、5、7、9周）将Wistar大鼠分为5组，每组8只，观察大鼠脑正常发育过程中视皮层PNN及Nogo受体的变化；（2）根据氟西汀给药周数不同将成年（出生后10周）大鼠采用完全随机化法分为对照组及氟西汀2、4、6、8周组，每组8只，观察不同给药时间对大鼠脑视皮层PNN及Nogo受体的影响；（3）设立双眼形觉剥夺（BFD）组作为阳性对照，按干预方式不同将成年（出生后10周）大鼠采用完全随机化法分为阴性对照组、氟西汀组、BFD组和BFD+氟西汀组，每组8只，观察不同干预方法对大鼠脑视皮层PNN和Nogo受体的影响效果。采用免疫荧光法观察各组大鼠脑视皮层Nogo受体和PNN的表达变化，采用免疫印迹法检测各组大鼠脑视皮层Nogo受体蛋白的表达。组间比较根据方差齐性与否，选择t检验、方差分析或秩和检验；多重比较采用Bonferroni法，并对检验水准进行调整；组内指标变化趋势采用简单线性回归分析。 结果： （1）随大鼠发育周龄增加，PNN（b=0.97，P=0.005）及Nogo受体阳性细胞密度（b=0.96，P=0.010）在视皮层呈逐渐增加；Nogo受体蛋白表达随出生后周龄逐渐增加（b=0.96，P=0.010），7周龄组（131.83±3.78）接近成年（9周龄组，135.11±3.92）水平（Z=1.93，P=0.062）。（2）免疫荧光显示氟西汀可显著降低成年大鼠视皮层的PNN，氟西汀喂养健康成年大鼠4周视皮层PNN阳性细胞密度（86.22±7.68）个/mm(2)与3周龄大鼠（84.21±6.68）个/mm(2)相当（t=2.08，P=0.073）。随氟西汀喂养周数增加，成年大鼠视皮层PNN（b=-0.88，P=0.040）及Nogo受体（b=-0.90，P=0.007）阳性细胞密度逐渐下降。（3）免疫荧光显示氟西汀组、BFD组及BFD+氟西汀组均较阴性对照组出现PNN（t=10.09、7.64、13.01；P=0.007、0.011、0.001）及Nogo受体阳性细胞密度（t=13.42、11.47、18.13；P=0.012、0.013、0.001）的下降；但氟西汀组与BFD组间Nogo受体比较差异无统计学意义（t=2.41，P=0.153）。免疫印迹显示氟西汀组、BFD组及BFD+氟西汀组相对阴性对照组Nogo受体蛋白的表达量分别为81.83±2.68、81.39±2.09及72.90±1.01，多组间差异有统计学意义（H=5.69，P=0.041）；且氟西汀联合BFD降低Nogo受体蛋白表达上与各自单独作用不同，表现为二者联合效果优于各自单独效果（氟西汀组与BFD+氟西汀组比较，Z=4.22，P=0.005；BFD组与BFD+氟西汀组比较，Z=3.09，P=0.010）。 结论： 大鼠脑视皮层的PNN和Nogo受体的发育呈视觉经验依赖性，随大鼠视觉发育，其视皮层PNN和Nogo受体逐渐增加；氟西汀可显著降低成年大鼠脑视皮层内的PNN和Nogo受体，且其效果与BFD相当。（中华眼科杂志，2019，55：37-45）.
Keywords: Fluoxetine; Neuronal plasticity; Nogo receptors; Perineuronal net; Visual cortex.