Effect of miR-731 on eye damage in rainbow trout (Onchorhynchus mykiss) infected with viral hemorrhagic septicemia

Among the various viral diseases in fish, viral hemorrhagic septicemia virus (VHSV) could be mentioned as the most significant viral infection which has now been identified for its worldwide devastating effects on trout. In the present investigation, the influence of the miR-731 on eye damage with exophthalmos (pop-eye) of VHSV in rainbow trout (O. mykiss) was examined. In current clinical trials, fishes (20± 1) g were examined to determine the possibility of pretreatment VHS disease by miR-731 in four main groups, including negative control without any injection, vehicle that received saline, positive control that were infected by VHSV (IP), and experimental group that were received miR-731 48 hour pre viral injection. Each main group subdivided into three subgroups. Carbonic anhydrase (CA) activity plays an important role in controlling aqueous production in the eye and in regulating intraocular pressure. The rate of carbonic anhydrase on trout eye was assessed in each group. Our results revealed that all animals in the positive control showed pop-eye, whereas in the negative control, the vehicle and the experimental groups were not observed any exophthalmos and there is significant difference between the rate of carbonic anhydrase in the positive control group and other groups. Although more studies are needed to verify the exact mechanisms of miR-731 viral inhibition pathway, present results partly proved that miR-731 pretreatment could decrease the sign of VHS disease eye damage.