Objective    To investigate the effects of taurine on the structure and function of retinal inner plexiform layer (IPL) of rats exposed to hypobaric hypoxia.     Methods    Sixty-four rats were randomly divided into 2 groups: normal diet group (N)

taurine supplemented group (T). Rats from normal diet group were fed with normal chew for 14 d

and then further divided into 4 subgroups

normoxia control (N

C)

and the groups (NH) who were placed into low pressure chamber to imitating 5 000 m high altitude for 1

3 or 7 d respectively. Rats fed with 2.4% taurine supplemented chew for 14 d were divided into 4 subgroups

that is

TC groups

and those in hypobaric hypoxia for 1

3 or 7 d respectively (TH groups). After the hypoxia treatment

IPL function was evaluated by testing oscillatory potentials (OPs) with RETI port system

by observing ultrastructure of IPL with transmission electron microscope

and by determining the average density of synapsin with immunohistofluorescence method.     Results    Prolonged latency and lower amplitude in OPs were found in rats exposed to 1 or 3 days’ hypobaric hypoxia of both NH and TH groups

but for those rats having 7 days’ exposure

the latency of their OPs reduced to relative normal value

but the amplitude was significantly lower in comparison to NC and TC groups (P0.05). There were significant difference in the latency of OS

2

wave between the NH rats and TH rats after 3 days’ exposure (P0.05)

and the OS

2

amplitude in TH groups were significantly higher than those in NH groups (P0.05). IPL of rats in NH groups showed swelling and swollen mitochondria in axon

disintegrated dendritic microtube

scarce synapses with depleted vesicle

while TH group displayed distinct synapses with abundant vesicles. Synapsin was mainly distributed in IPL of every group. Compared with NC group

the density of synapsin decreased in rats exposed to hypoxia for 1 or 3 d in both groups (P0.05). But in TH 1 d group

the synapsin density was significantly higher than the NH 1 d group (P0.05).     Conclusion    Taurine ameliorates the retinal IPL damage of rats suffering from acute hypobaric hypoxia.