Effects Of LBA On The Critical Periods Of Visual Plasticity In Rats With Visual Deprived Amblyopia

Objective:To construct the rat models of monocular visual deprived amblyopia, to investigate the possible neuroprotection of LBA on the retinal ganglion cells (RGCs) in rats with visual deprived amblyopia.Methods:A total of 30 postnatal Wistar rats were randomly divided into Normal Saline group (10), L-dopa group (10) and LBA group (10). After postnatal 1 week, the left palpebras of all rats was sewed by mattress suture in order to construct the models. Each day three groups were respectively fed with the same amount of 0.9% NaCl,20mg/kg L-dopa and 10mg/kg LBA up to 6 weeks. RGCs were retrograde labeled by injection of 30g/L fluorogold (FG) into bilateral superior colliculi and lateral geniculate body 5 days before the death in all rats, then the RGCs changes of morphology and numbers in retinal flat were observed.Results:①The labeled RGCs in retinal flats were yellow-white with various morphology, the cellular prominence with fluorescence could be seen.②RGCs density of left eyes in the three groups were obviously lower than right eyes, the differences were significant (P<0.01).③Compared with NS group, RGCs density of left eyes were obviously higher in L-dopa and LBA group (P<0.01), but there was no significance between L-dopa and LBA group (P>0.05).④The survival rates of RGCs in L-dopa group (85.17%±4.42%) and LBA group (84.31%±5.97%) were obviously higher than NS group (71.35%±6.34%, P<0.01), but there was no significance between L-dopa group and LBA group (P>0.05).Conclusion:①LBA might have neuroprotection on RGCs in rats with deprived amblyopia during the critical periods of visual plasticity and then increase the survival rates of RGCs.②The visual neuroprotection of LBA on RGCs is similar to L-dopa, which is used as conventional medicine in amblyopia therapy. Objective:To construct the rat model with monocular deprived amblyopia, to investigate the effects of LBA on Bcl-2 and NGF expression in visual cortex area 17 in the different sensitive periods of visual development.Methods:60 postnatal Wistar rats were randomly divided into normal group (12), normal saline group (24), LBA group (24). One week after left eyelid mattress sulture in NS group and LBA group, rats were respectively fed with the same amount of 0.9% NaCl and 10mg/kg LBA each day, while normal group were fed freely. In postnatal 14d,21d,28d, 35d,42d and 70d, rats were executed. Tissue sections were used to measure the neuron numbers and sectional areas in visual cortex area 17 by Nissl staining, then detect the corresponding expression of Bcl-2 and NGF by SABC immunohistochemistry.Results:①Nissl staining showed unsharp layering of the right visual cortex in deprived amblyopia rats, loose arrangement, irregular morphology and prominence, reduction of Nissl bodies, apperance of pyknosis and dark staining.②The neuron numbers and sectional areas in right visual cortex of LBA group were obviously higher than the corresponding area in the evenaged NS group from P28 to P70 (P<0.05).③The positive cell numbers of Bcl-2 and optical density (OD) in right visual cortex of LBA group were obviously higher than the evenaged NS group from P21 to P70 (P<0.05).④The positive cell numbers of NGF and OD in right visual cortex of LBA group were higher than the evenaged NS group from P14 to P28 (P<0.05).Conclusion:①In the sensitive stage of visual development, deprived amblyopia in rats might reduce the cell numbers and sectional areas in visual cortex, which were lower than normal group.②LBA might have neuroprotection during the critical period of visual plasticity in deprived amblyopia rats, and be used as an alternative drug for amblyopia treatment.③The neuroprotective mechanism of LBA on visual development in deprived amblyopia rats might be related with up-regulating the expression of Bcl-2 and NGF, which could improve nutrition and growth of the nerve cells.