Objective   To investigate the effects of chondroitin sulfate proteoglycans (CSPGs) degradation induced by chondroitinase ABC (ChABC) on the rat flash visual evoked potential (F-VEP) around the end of the critical period of visual development.    Methods   A total of 30 Long Evans rats were randomly divided into 3 groups according to their age of 14

21 and 35 d. Then in each group

5 animals served as CSPGs degradation model induced by ChABC microinjection into 5 sites of the rat cortex [750 nL (48 U/ml) for 1 site

for 2 times at a 3-day interval]

and the other 5 rats served as normal control and received normal saline microinjection. Immunofluorescence microscopy and laser scanning confocal microscopy were used to determine the establishment of animal model. F-VEPs were evaluated in 7 d after first microinjection.    Results   In the normal rats

the latency of F-VEP main wave became shorter with the increase of their age

the number was [(63.5±10.1)

(50.8±6.4)

(44.9±6.3) ms

P0.05]

whereas the amplitude of F-VEP main wave was first increased from (15.7±3.8) ms to (26.6±4.0) ms at early postnatal days (P0.05) and decreased slightly at postnatal day 49. In the ChABC treated rats

the latency of F-VEP main wave became longer than that of normal rat on postnatal day 35 and 49

the number was （62.5±8.0），（58.4±7.6）ms  (P0.05). But there was no obvious change of the F-VEP amplitude between the normal rats and ChABC treated rats.    Conclusion   Around the end of the critical period of visual development

CSPGs degradation has an effect on the development of rat F-VEPs.