[Introduction]: This is an experimental study. [Purpose]: We aimed to evaluate the effect of somatostatin (SS) on cellular viability of retinal ganglion cells and retinal explants. In addition, we investigated the possible effects of SS by modulating protein tyrosine phosphatase 1B (PTP1B). Methods. RCG5 cells were cultured under normoxia or hypoxia (1% oxygen) either with normal (5 mM) or high (55 mM) glucose in the absence or presence of SS (10-6 M). Cellular viability was analyzed by crystal violet staining along 72 h of culture. Retinas were isolated from 3 month-old male mice (C57/BL6 × 129 sv) and cultured in R16 medium in the conditions described above. Total RNA was isolated and PTP1B and VEGF mRNA levels were determined by quantitative PCR. [Results]: Under normoxic conditions, RGC5 cells proliferate along 72 h of culture regardless the presence of normal or high glucose in the culture medium. In these experimental conditions, SS did not affect the proliferation rate. However, cellular viability of RCG5 cells cultured in hypoxic conditions under normal glucose significantly decreased at 48 h and was maintained at similar low levels up to 72 h. The presence of high glucose further decreased cellular viability at 72 h. SS was able to recover cellular viability of RCG5 cells cultured under hypoxia and hyperglycemia. Due to the involvement of PTP1B in cell proliferation-mediated signaling, we determined PTP1B mRNA levels in retinal explants cultured under conditions of diabetic milieu. PTP1B mRNA levels significantly increased at 72 h of culture of retinal explants in high glucose and both normoxia or hypoxia. The presence of SS was able to decrease PTP1B mRNA levels. To further assess our experimental conditions in retinal explants, we analyzed VEGF mRNA levels. Hypoxia and hyperglycemia induced VEGF mRNA at 24 h, these effects being significantly inhibited in the presence of SS. [Conclusions]: Our results indicate that SS is involved the maintenance of viability of RCG5 cells in conditions of diabetic milieu. Moreover, data in retinal explants suggest that modulation of PTP1B might be a potential molecular mechanism for this effect.

Resumen del trabajo presentado al 23rd Meeting of the European Association for the Study of Diabetes Eye Complications Study Group (EASDec), celebrado en Barcelona (España) del 23 al 25 de mayo de 2013.

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