| Summary: | 碩士 === 國立臺灣大學 === 獸醫學研究所 === 94 === The term polyarteritis nodosa（PAN）has been used to denote periarteritis in several species of animals. The condition was first comprehensively documented in 1866 in man Kussmaul and Maier. The lesions of the disease develop in small and medium sized arteries anywhere in the body and the reaction involves all layers of the vessel wall. In domestic animals are seen sporadically. In most cases, the cause of polyarteritis nodosa remains unknown, but viruses and microbes have been considered as etiologic or contributing factor. According to some references, many authors believe the Streptococcus suis type 2 is an important factor but still isn’t demonstrated. Between September in 2004 and December in 2005, a total of 120 pig brains with 113 locomotor disturbances were collected from the slaughterhouse. 6 of 120 brain samples（6/120, 5％）showed arteritis or periarteritis lesion varying degrees of leptomeninges and irregular, thickened leptomeninges with congested blood vessels were observed in the gross lesion. One PAN-like lesion showed IHC positive for S. suis type 2. The expression of macrophage inflammatory protein–2 (MIP-2) mRNAs analyzed by reverse transcriptase–PCR (RT-PCR) in mouse brain microvascular endothelial cells (CRL-2299) by co-culture with different S. suis type 2 concentration（101 to 105 CFU/ml）for 12 hours. The expression of MIP-2 mRNAs significantly increased as compared with untreated cells. The expression of MIP-2 mRNAs analyzed by real-time PCR also significantly increased as compared with untreated cells. MIP-2 peptide levels were measured by the ELISA. The protein levels of the supernatant from CRL-2299 were measured after exposure to 101 to 105 CFU/ml S. suis type 2 for 12 h and in the case of blocking experiments. The MIP-2 peptide significantly increased as compared with untreated cells（P＜0.05; P＜0.01）. The collagen type IV was analyzed by western blot. The CRL-2299 treated with S. suis type 2 101 and 103 CFU/ml for 24 hours revealed 200-kD protein bands. The protein significantly increased as compared with untreated cells (P＜0.05). Based on the results of IHC and expression of MIP-2 and collagen type IV, S. suis type 2 infection may play a role to the formation of PAN.
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