ABSTRACT
OBJECTIVE: To study the influence of long-term gamma-irradiation with low dose rate (13×10-6 cGy/s) on the body, testes and ventral prostate, development of laboratory rats, as well as quantitative parameters of sperm production along with kinetic characteristics of spermatozoa. MATERIALS AND METHODS: The experiments were performed on laboratory white rats of 2,5 months in age. Animals were irradiated in gamma-field of "Ethalon" device in a dose range 0.1-1.0 Gy. Testicles, epididymises, ventral prostate were retrieved from decapitated animal, each organ weight being determined for every exposure dose. Sperm quantities in testicles and epididymises were identified with aid of phase-contrast microscopy after tissue homogenization in saline containing Troton X-100 and NaN3. Kinetic characteristics of spermatozoa were analyzed by video recording at 37 ºC. RESULTS: The long-term gamma-irradiation with low dose rate was shown to cause no effect on the dynamics of animal weight and weight of epididymis changes. However the testes weight was noticed to diminish at doses 0.1, 0.3, 0.6 and 1.0 Gy, the latter dose being stimulative for the ventral prostate growth and weight accumulation. Total sperm quantities in testicles and epididymices along with daily sperm production declined in gamma-irradiated rats compared to control. However curvilinear and straight line spermatozoid velocity as well as the frequency of tail oscillations tended to increase. CONCLUSIONS: Long-term gamma-irradiation of rat whole body with low dose rate just insignificantly affects the development of testes and ventral prostate. Apart from this, radiation effects showed up in sperm production slight suppression, from the on hand, and sperm velocity along with tail oscillations intensification, from the other hand.
ABSTRACT
Objective. Show the possibility of method of the radiocapacity factor using for the study the phenomenon of adaptation of maize plants to the action of toxic factor - namely , introducing into the habitat of cadmium chloride solution. This method is proposed as convenient and adequate indicator of change of state of the objects under chemical stressor influence. Materials and methods. Experiments were performed in the laboratory, the object of research were the processes of water culture of maize plants (Zea Mays L.) variety Prydnistrovska adapting to the toxic metal action. Cadmium chloride solution was entered to the culture medium of plants at concentrations, selected according to the standard adaptive scheme of the experiment. Under this scheme, adaptive concentration (1 µM/L and 2 µM/L of salt CdCl2) was entered first, and through certain time (Δt) - test concentration (25 µM/L of salt CdCl2). The assessment of maize plants adaptation was carried out by the changing of growth parameters and of radiocapacity factor. The radiocapacity factor defined as the ratio of current activity in water (medium) by the specifically inserted tracer - 137Cs to the initial. Results and conclusions. The radiocapacity factor concentration dependence and dependencies under adaptive and stress influences to plants was obtained. The dependence of adaptation on the time interval between the test and adapting concentrations of cadmium chloride was revealed. And the effect of sensibilization on the growth and absorbing characteristics of plants of salt CdCl2 when the test concentration 25 µM/L entered at 4 hours after adaptive concentrations (1 µM/L and 25 µM/L) application was observed. It is shown that the radiocapacity factor is adequate, sensitive and efficient indicator manifesting the response of plants to stress influence in the conditions of adaptive schemes of influence using.
ABSTRACT
OBJECTIVE: To show the possibility of a new approach using for the evaluation of biota's state in the ecosystem under the independent and combined effect of radiation and chemical factors. It is based on a radiocapacity factor analysis, defined as the maximum radionuclide quantity accumulated in biotic components of ecosystem that does not disturb major biota's functions. MATERIALS AND METHODS: Experiments were performed in the laboratory, where water culture of maize plants served as a simplified two-component model of ecological system as a "biota-environment" type. Plants were exposed to independent and combined effects of acute and fractionated γ-irradiation and CdCl2 salt application. The assessment of state of the biotic component i.e. the maize plants was performed by the growth parameters and changes of radiocapacity factors. The radiocapacity factor was defined as the ratio of current activity in water (medium) by the specifically inserted tracer - 137Cs to the initial value. RESULTS AND CONCLUSIONS: According to our experimental data, the proposed parameter for the assessment of biotic components of the system state - the radiocapacity factor, proved to be very sensitive to influence of both radiation and chemical factors on the biota. Its response is corrected with the reaction of growth parameters and has been advanced compared to them. Therefore, it is appropriate to consider the possibility of radiocapacity factor using for the assessment of plants state under the harmful influences. In addition, based on the theory of radiocapacity, a model for the assessment of combined action of radiation (γ-exposure) and chemical factors (cadmium chloride) on the model of plant system has been developed and proposed. Thus, through the assessing the value of the proposed characteristics of interaction i.e. the synergism index we got an opportunity to draw the conclusions about the character of interaction of radiation and chemical factors that varies from synergy to antagonism.
