Distribution of 131I-labeled Bothrops erythromelas venom in mice.

C.M.L Vasconcelos,E.A Araújo,T.K Brazil,M.M Pontes,M.C Guarnieri,J.C.A Modesto,R.C Valença

doi:10.1590/s0100-879x1998000300017

Abstract

Bothrops erythromelas is responsible for many snake bites in northeastern Brazil. In the present study we determined the in vivo distribution of the venom following its subcutaneous injection into mice. B. erythromelas venom and albumin were labeled individually with 131I by the chloramine T method, and separated in a Sephacryl S-200 column. The efficiency of labeling was 68%. Male Swiss mice (40-45 g), which had been provided with drinking water containing 0.05% KI over a period of 10 days prior to the experiment, were inoculated dorsally (s.c.) with 0.3 ml (2.35 x 10(5) cpm/mouse) of 131I-venom (N = 42), 131I-albumin or 131I (controls, N = 28 each). Thirty minutes and 1, 3, 6, 12, 18 and 24 h after inoculation, the animals were perfused with 0.85% NaCl and skin and various organs were collected in order to determine radioactivity content. There was a high rate of venom absorption in the skin (51%) within the first 30 min compared to albumin (20.1%) and free iodine (8.2%). Up to the third hour after injection there was a tendency for venom and albumin to concentrate in the stomach (3rd h), small intestine (3rd h) and large intestine (6th h). Both control groups had more radioactivity in the digestive tract, especially in the stomach, but these levels decreased essentially to baseline by 12-18 h postinjection. In the kidneys, the distribution profiles of venom, albumin and iodine were similar. Counts at 30 min postinjection were low in all three groups (1.37, 1.86 and 0.77, respectively), and diminished to essentially 0% by 12-18 h. Albumin tended to concentrate in muscle until the 3rd h postinjection (1.98%). There was a low binding of labeled venom in the liver (< 0.54%), thyroid (< 0.11%) and lungs (< 0.08%), and no iodinated venom was detected in brain, heart, diaphragm, spleen or bladder. The low venom binding observed in most internal organs, comparable to that of albumin, suggests that B. erythromelas venom does not specifically target most internal organs. That is, the systemic effects of envenomation are mainly due to an indirect action.

Highlights

Bothrops erythromelas, commonly known as “jararaca-da-seca” or “jararacamalha-de-cascavel”, is responsible for many snake bites in northeastern Brazil [1,2]
Recent studies on dogs performed in our laboratory have shown that B. erythromelas venom induces hemostatic changes involving hypercoagulable blood followed by incoagulable blood [6] and intense hemorrhage in the lungs, kidneys and liver [11]
In the present study we examined the distribution of 131I-labeled B. erythromelas venom in mice following subcutaneous injection

Summary

Introduction

Commonly known as “jararaca-da-seca” or “jararacamalha-de-cascavel”, is responsible for many snake bites in northeastern Brazil [1,2]. In the present study we examined the distribution of 131I-labeled B. erythromelas venom in mice following subcutaneous injection. Mice were divided into two groups: controls (N = 56) were injected dorsally (sc) with 0.3 ml of 131I or 131I-labeled albumin while experimental animals (N = 42) received 131I-labeled venom.

Results

Conclusion