Brown spider dermonecrotic toxin directly induces nephrotoxicity.
Brown spider (Loxosceles genus) venom can induce dermonecrotic lesions at the bite site and systemic manifestations including fever, vomiting, convulsions, disseminated intravascular coagulation, hemolytic anemia and acute renal failure. The venom is composed of a mixture of proteins with several molecules biochemically and biologically well characterized. The mechanism by which the venom induces renal damage is unknown. By using mice exposed to Loxosceles intermedia recombinant dermonecrotic toxin (LiRecDT), we showed direct induction of renal injuries. Microscopic analysis of renal biopsies from dermonecrotic toxin-treated mice showed histological alterations including glomerular edema and tubular necrosis. Hyalinization of tubules with deposition of proteinaceous material in the tubule lumen, tubule epithelial cell vacuoles, tubular edema and epithelial cell lysis was also observed. Leukocytic infiltration was neither observed in the glomerulus nor the tubules. Renal vessels showed no sign of inflammatory response. Additionally, biochemical analyses showed such toxin-induced changes in renal function as urine alkalinization, hematuria and azotemia with elevation of blood urea nitrogen levels. Immunofluorescence with dermonecrotic toxin antibodies and confocal microscopy analysis showed deposition and direct binding of this toxin to renal intrinsic structures. By immunoblotting with a hyperimmune dermonecrotic toxin antiserum on renal lysates from toxin-treated mice, we detected a positive signal at the region of 33-35 kDa, which strengthens the idea that renal failure is directly induced by dermonecrotic toxin. Immunofluorescence reaction with dermonecrotic toxin antibodies revealed deposition and binding of this toxin directly in MDCK epithelial cells in culture. Similarly, dermonecrotic toxin treatment caused morphological alterations of MDCK cells including cytoplasmic vacuoles, blebs, evoked impaired spreading and detached cells from each other and from culture substratum. In addition, dermonecrotic toxin treatment of MDCK cells changed their viability evaluated by XTT and Neutral-Red Uptake methodologies. The present results point to brown spider dermonecrotic toxin cytotoxicity upon renal structures in vivo and renal cells in vitro and provide experimental evidence that this brown spider toxin is directly involved in nephrotoxicity evoked during Loxosceles spider venom accidents.
Chaim
Olga Meiri
OM
Department of Cell Biology, Federal University of Paraná, Jardim das Américas, 81531-990, Curitiba, Paraná, Brazil.
Sade
Youssef Bacila
YB
da Silveira
Rafael Bertoni
RB
Toma
Leny
L
Kalapothakis
Evanguedes
E
Chávez-Olórtegui
Carlos
C
Mangili
Oldemir Carlos
OC
Gremski
Waldemiro
W
von Dietrich
Carl Peter
CP
Nader
Helena B
HB
Sanches Veiga
Silvio
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D018076:DNA, Complementary / Q000032:analysis; D004285:Dogs; D042783:Endothelial Cells / Q000187:drug effects* / Q000648:ultrastructure; D015723:Gene Library; D019476:Insect Proteins / Q000235:genetics; D007668:Kidney / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D007674:Kidney Diseases / Q000139:chemically induced* / Q000473:pathology; D051379:Mice; D008969:Molecular Sequence Data; D009336:Necrosis / Q000139:chemically induced; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000633:toxicity*; D011817:Rabbits; D011994:Recombinant Proteins; D012867:Skin / Q000473:pathology*; D013111:Spider Venoms / Q000235:genetics / Q000633:toxicity*; D013112:Spiders / Q000235:genetics
D018076:DNA, Complementary; D019476:Insect Proteins; D011994:Recombinant Proteins; D013111:Spider Venoms; C055161:loxosceles venom; D010727:Phosphoric Diester Hydrolases