Abstract:

The current study was undertaken to research the effects of histamine H₁- and H₂-receptor antagonists on HP-PRRS swine pneumonia.A total of 20 piglets，weaned at 30 days of age (8.9-11 kg body weight)，were assigned to four groups (5 piglets per group)：positive group (CG)，negative group (EG)，Chlorphenamine maleate group (CM)，Cimetidine group (CMT).HP-PRRS model was established by injecting PRRSV to piglets intramuscularly.Numbers of lung macrophage were determined and lung pathological changes of every group were graded with HE staining.The content of Histamine was determined by using traditional method，the content of IL-1 and TNF-α were determined by using ELISA method.The copied number of nucleic acid of PRRSV was detected by real time-PCR.The results showed that：1) HP-PRRS models of piglet were successfully established.2) The numbers of lung macrophage of CM group were extremely lower significantly (P＜0.01) than CG and CMT group.3) The lung tissue and structure were normal in negative group，the groups infected PRRSV appeared varying degrees pathological change，the lung pathological score of piglets in positive group were significant lower (P＜0.05) than CMT group，the CM group were significant lower (P＜0.01) than CG and CMT group.4) Compared with EG group，the content of histamine in CG and CMT group were significantly (P＜0.05) or significantly higher (P＜0.01)，the content of histamine in CM group were significantly lower (P＜0.01) than CG group.5) The content of IL-1 and TNF-α in the HP-PRRS infected swine were extremely significant higher (P＜0.01) than EG group.6) The PRRSV nucleic acid copy numbers of CM and CMT groups were significantly lower (P＜0.01) than CG group.These results indicated that the histamine H₁ antagonists (chlorpheniramine maleate) can reduce the inflammation response in HP-PRRS infected swine.