The Study of Histopathological Effect of H9N2 Sub-type Influenza Virus on SPF Chicks Airway
Influenza is a viral disease which has been known in 1901AD in 1955, a kind of influenza virus was known as a factor caused disease that later on called avian plague because of high rate mortality. In the present study, the sub-type H9N2 of avian influenza virus (obtained from Razi Serum Producing and Research Center) which was cloned two times in embryonic eggs was inoculated to the SPF (Valo, Lohman, Germany) at their 3rd week by nasal drops: At first, SPF chickens were divided to 2 groups of 10 subjects; a group as a treatment group and another one as a control group. Then treatment group was infected by H9N2 sub-type of influenza virus with dosage of 107.5 EID50. The control group obtained normal saline serum nasally equal to the inoculated viral solution volume. In histopathological studies of lung and pleura of treated chicks with H9N2 sub-type influenza virus, propagated pneumonia which accompanies hyperemia and severs hemorrhage was observed in to allele and pleurisy sacs. In microscopic view, there is sever hyperemia and hemorrhage in allelic sacs, edama infiltration of fibrin and inflammatory cells, especially heterophylus in pulmonary' tissue inter-space. In the present study, the apoptosis of primary bronchial cells was observable in some cases which demonstrate significant changes compared with control group. Probably, the expression of apoptosis induction channel which has been discussed in Brydon's studies is a suitable justification for these changes. So, it must be noted that there are various channels in occurrence of cell death following infection by influenza virus and knowing these channels needs extensive studies.