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Studies showed that traumatic optic neuropathy (TON) can activate and induce immuno-inflammatory response, while T helper cell 17 (Th17), a CD4+ T lymphocyte, is associated with immuno-inflammatory response.However, the effects of Th17 on the development of TON are unclear.
This study was to observe the changes of Th17 lymphocytes in spleen and the expression of interleukin-17 (IL-7) in retina in TON rats.
Seventy male 4-week-old SD rats were randomly divided into normal control group, sham operation group and TON 1-, 3-, 7-, 14- and 28-day group according to random number table.The optical nerves of the right eyes were exposed and impacted at a 25° angle by using fluid percussion injury (FPI) device with the average force (699.1±60.8) kPa to create the TON models in the TON groups, and only optical nerves were exposed in the sham operation group.Flash visual evoked potential (F-VEP) was recorded and the amplitude and latency were measured to evaluate the function of optical nerves of the rats.The rat splenocyte suspension in various groups was prepared for the detection of Th17 cells by flow cytometry, and the expression of IL-17 protein was detected by immunochemistry.
No significant differences were found in the amplitudes and latencies of P2 wave, proportion of Th17 cells and the IL-17 positive cell numbers in retina between the normal control group and sham operation group (P=0.829, 0.830, 0.856, 0.496). The amplitudes of P2 wave were significantly lower, and the latencies of P2 wave were significantly longer in the TON groups than those in the sham operation group (all at P<0.05). The proportions of Th17 positive CD4+ T lymphocytes were (0.94±0.13)%, (1.80±0.18)%, (1.98±0.20)%, (2.34±0.20)%, (2.11±0.13)%, (1.92±0.18)% in the sham operation group, TON 1-day group, TON 3-day group, TON 7-day group, TON 14-day group and TON 28-day group, respectively, showing significant differences between the sham operation group and various TON groups (all at P<0.05). In addition, the IL-17 positive cell numbers in retina were 796.326±100.028, 1 673.416±188.021, 1 892.431±151.026, 2 420.454±256.024, 1 996.429±177.022 and 1 629.410±127.023 in the sham operation group, TON 1-day group, TON 3-day group, TON 7-day group, TON 14-day group and TON 28-day group, respectively, showing significant differences between the sham operation group and various TON groups (all at P<0.05).
In rats of TON, the proportion of Th17 cell in splenocytes and the expressions of IL-17 in retina are increased, suggesting that Th17 and IL-17 participate in the progression of TON.