60Co GAMMA RADIATION EFFECTS ON Apis mellifera VENOM: BIOCHEMICAL, PHARMACOLOGICAL, AND IMMUNOLOGICAL ASPECTS

⁶⁰Co GAMMA RADIATION EFFECTS ON Apis mellifera VENOM: BIOCHEMICAL, PHARMACOLOGICAL, AND IMMUNOLOGICAL ASPECTS

THESIS. H. Costa submitted this thesis for her Doctorate in Nuclear Technology publicly examined at the Institute of Nuclear and Energy Research of São Paulo University, São Paulo, Brazil, 2001.

Advisor: Prof. Dr. José Roberto Rogero

ABSTRACT. Africanized honeybees are very common in Brazil and frequently cause envenomings followed by important immunological reactions and even death. Their venoms are composed of a complex mixture of substances of general biological actions. Ionizing radiation is able to modify molecular structures affecting the biological properties of proteins. It decreases toxic and enzymatic activities and appears to be a promising venom detoxification tool. The main objective of this work was to study the effects of gamma radiation on the biochemical, pharmacological, and immunological aspects of bee venom. Africanized Apis mellifera whole venom (2 mg/ml) in 0.15M NaCl solution was irradiated with 2 kGy in a ⁶⁰Co source. Native and irradiated bee venoms were submitted to high performance size exclusion chromatography (Tosohaas G2000SW column), high performance reversed phase chromatography in a C-18 column under water/acetonitrile gradient, and SDS-PAGE. For both venoms, studies were made for UV absorption spectrum, protein concentration, hemolytic activity, PLA2 activity analysis, and lethality assay (LD50). Biodistribuiton studies were carried out after labeling native and irradiated bee venom with ^99mTc. The results showed that gamma radiation did not change protein concentration or immunogenicity, although differences were observed in UV spectrum and SDS-PAGE profile between irradiated and native bee venom. This suggests that some structural alterations in bee venom components could have occurred after irradiation. HPLC-RP profiles showed that gamma radiation could have caused conformational changes, such as unfolding of molecule chains, changing their hydrophobic group exposure. Hemolytic and PLA2 activities of irradiated venom were lower than native venom. Gamma radiation reduced bee venom toxicity but did not stop its bioactivity, like hemolysis. Biodistribution studies showed that native and irradiated bee venom were rapidly absorbed and suggest that they have hepatic metabolism and renal elimination. Irradiated bee venom seems to be eliminated faster than native venom, which could explain its reduced toxicity.

KEY WORDS: Bee venom, gamma radiation, detoxification.

CORRESPONDENCE TO:

H. COSTA - IPEN/CNEN, Travessa R, 400 - Cidade Universitária, 05508-970, São Paulo, S.P., Brasil.

E-mail: [e-mail]

Publication Dates

• Publication in this collection
  13 May 2002
• Date of issue
  2002