Enteropathogenicity of Diarrhetic Shellfish Toxins in Intestinal Models

Abstract

Enteropathogenicityof diarrhetic shellfish toxins (DST) was evaluated in rabbit intestinal loops, mouse intestinal loops and suckling mice, by using the methods established for the detection of bacterial enterotoxins.Crude toxin of DST (cr-DST) was prepared by acetone extraction from scallops (Patinopecten yessoensis) implicated in the poisoning outbreaks in Osaka in 1978 and 1982. Individual DSTs such as dinophysistoxin-1 and -3 (DTX-1 and DTX-3), pectenotoxin-1 (PTX-1) and okadaic acid were also tested on suckling mice for diarrheagenicity.The rabbit loop injected with 8 MU of cr-DST showed significant fluid accumulation in 18 hours. The mouse loop injected with 0.8 MU of cr-DST also showed significant fluid accumulation in 6 hours. In the suckling mouse test, positive results were observed with 0.1 MU of cr-DST in 4 hours.The small intestines with fluid accumulation in the loop tests were sectioned and stained with hematoxylin-eosin for histopathological studies. Destruction of epithelium and edema of the lamina propria were observed.In the suckling mouse test, DTX-1, DTX-3 and okadaic acid showed positive results, whereas PTX-1 did not.From these data, we concluded that DST shows enterotoxic activities in these animal models and that okadaic acid, DTX-1 and DTX-3 are diarrheagenic.

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“…Injection of OA and other diarrhoeic shellfish toxins into mice causes vessel congestion and extravasation into the lamina propria (Hamano et al, 1986;Terao et al, 1986), and instillation of DTX1 in ligated loops of the rat intestine leads to rapid fluid accumulation (Edebo et al, 1988). In line with these observations sprinkling of rat colon with OA was found to cause mucosal oedema and submucosal fluid accumulation (Hosokawa et al, 1998).…”

HIGH AMOUNT OF DINOPHYSISTOXIN-3 IN Mytilus chilensis COLLECTED IN SENO DE RELONCAVI, CHILE, DURING MASSIVE HUMAN INTOXICATION ASSOCIATED WITH OUTBREAK OF Vibrio parahaemolyticus

“…If intoxication level is mild, the syndrome favorably evolves toward total recovery into one to three days illness. No fatalities have been recorded (Yasumoto et al, 1978;Hamano et al, 1986;Aune et al, 1998;García et al, 2003García et al, , 2004García et al, , 2005.…”

Shellfish Toxins − Chemical Studies on Northern Adriatic Mussels

“…Histopathological investigations in mice injected with PTX2 revealed severe mucosal injuries and fluid accumulation in the small intestine and revealed that it is hepatotoxic and induces rapid necrosis of hepatocytes. [27] In addition, PTXs show a potent cytotoxicity [20,28,29] and probably inhibit actin polymerization.…”

“…The first incidence of human shellfish-related illness identified as DSP occurred in Japan in the late 1970s, where the dinoflagellate Dinophysis fortii was identified as the causative organism, and the toxin responsible was termed dinophysistoxin 1 (DTX1). [19,20] The OA class toxins are diarrhetics [20,21] and tumor promoters. [22] The mechanism of action underlying these activities is explained mainly by their potent inhibitory action against ser/thr protein phosphatases.…”