PhD, Associate Professor E.A. Yakimova
Mordovia State Pedagogical Institute named after M.E. Evsevev, Saransk

Keywords: lipid peroxidation, antioxidant protection, malonic dialdehyde, biological rhythms, muscular activity, exercise.

Introduction. Lipid peroxidation (LPO) is a process that occurs continuously in all living organisms and is important not only in the hominal physiology of cells, but also under stresses. Exercise is one of such stresses for the body, and therefore it is very important to study individual characteristics of the response to it of various functional systems [3], including LPO processes. It is now known that exercise impacts the ratio of activity of peroxidation and antioxidant protection. It has been found that people adapted to endurance exercise have a reduced lipid peroxidation level and an increased amount of antioxidants in the muscles. People adapted to exercise associated with speed and strength demonstrate an increase in lipid peroxidation intensity [4].

Literature related to the issues of the impact of exercises on lipid peroxidation is often contradictory. For example, there is evidence of both intensification of lipid peroxidation after muscular work and a reduction in lipid peroxides after exercise. N.V. Kurguzova and S.P. Golyshenkov (1996) observed pronounced individual characteristics of peroxidation processes’ response to exercise and therefore defined special response units [6]. A reduced lipid peroxidation response to muscular activity probably indicates a high level of compensatory-adaptive reactions of the body. According to S.P. Golyshenkov et al. (2004), lipid peroxidation metabolites can have an indirect regulating effect on aggregative properties of platelets [1]. Data obtained in the course of the studies of M.V. Lapshina (2015) suggest that lipid peroxidation processes have a linear correlation with the change in fibrinolytic activity of erythrocytes during muscular work [7].

S.N. Suplotov and E.N. Barkova (1985), studying daily and seasonal rhythms of lipid peroxides and superoxide dismutase (SOD) activity in erythrocytes of mid-latitude and Far North residents, found that the MDA concentration in healthy subjects aged 20-30 years old is subject to statistically significant fluctuations throughout the day and year. In particular, in mid-latitude residents the maximum concentration of lipid peroxides in autumn was recorded at night time, in winter – in the morning, in spring and summer – in the afternoon. The MDA daily mean value of mid-latitude residents is the lowest in the winter time and the highest in the spring time. Far North residents had their daily mean values of MDA significantly higher in autumn, winter and spring months. This difference is probably due to the fact that the complex of extreme factors of the mentioned region activates the lipid peroxidation processes by stimulating the activity of enzymatic and non-enzymatic systems of antioxidant protection. Based on the data of the adaptive function of SOD the authors also studied biorhythmological changes of the enzyme and found that in mid-latitude and Far North territories the lowest activity of SOD is recorded in the autumn time and the highest – in the spring time. During the day the maximum SOD concentration values are recorded in the afternoon for the autumn and winter time and in the evening for the spring and summer time. Analyzing biorhythmological MDA and SOD indices, the authors concluded that their average daily values reach their maximum in spring, and the high concentration of lipid peroxides induces strain of the SOD adaptive function [8].

Objective of the study was to identify the seasonal dynamics of some lipid peroxidation indices under the influence of intensive muscular work.  

Methods and structure of the study. The influence of graduated exercise on the seasonal dynamics of lipid peroxidation was studied by observing changes in concentration of malondialdehyde (MDA) as an interim lipid oxidation product (LOP). Subject to the study were 33 individuals aged 18.12 ± 0.19 years, 170.2 ± 1.24 cm tall and weighing 63.06 ± 1.13 kg, PWC_{170 rel.} 1.61 ± 0.03 W/kg), students of Mordovia State Pedagogical Institute named after M.E. Evsevev.

Blood samples for the research were drawn from the median cubital vein 10 minutes before the exercise and during the 1^st-2^nd minutes of the recovery period and stabilized with 3.8% sodium citrate. After 5 minutes of cooling in the refrigerator they were centrifuged for 10 minutes at the speed of 1,500 rounds per minute, and then platelet-rich plasma was collected. The remaining blood was cooled for 10 more minutes, then centrifuged for 30 minutes at the speed of 3,000 rounds per minute, and platelet-free plasma was collected. The MDA concentration in the platelet-poor plasma and haemolysate was identified using the blood samples.

A one-time 20-minute long exercise on a cycle ergometer “Rhythm CE-05” with the capacity of 80-85% of the individual maximum heart rate (HR) was performed as a test. The power of the muscular work performed was 106–199 W (2.0–2.78 W/kg), which corresponds to work in a high-power zone [9].

The research results were processed by variation statistics methods using Student’s t-test. 

The study was conducted at the premises of Applied Research Center of Physical Culture and Healthy Lifestyle of the Mordovia Basic Center of Pedagogical Education (MBCPE) in Saransk [5].

Research results and discussion. Study of lipid peroxidation processes showed that in a state of relative physiological rest the average MDA concentration in plasma during the warm seasons (spring-autumn) is significantly higher (by 71.06%) compared to the cold seasons (autumn-winter), which indicates intensification of the lipid peroxidation processes and reduced functions of the antioxidant system. Values of the MDA concentration in haemolysate remain relatively constant throughout the year.  

Physical load evoked diverse changes in the MDA concentration in the blood plasma and haemolysate throughout the year. For example, the MDA concentration is on the fall in the transitional seasons (autumn and spring time), the decrease being statistically significant only in the spring months (by 18.72%); and the MDA concentration is on the rise considerably in the winter and summer time (by 14.24% and 16.99%, respectively). The MDA concentration in haemolysate as a result of muscular activity showed significant growth in the autumn and winter time (by 17.37-49.1%). Thus, LOP processes are more active in the winter time and somewhat inhibited in the spring time under high-intensity physical loads.

As earlier we allocated all the subjects into groups depending on the response of the clotting and fibrinolysis systems to the proposed physical load [2, 10], it is interesting to trace differences in the seasonal dynamics of lipid peroxidation indices in representatives of the designated groups.

When allocating the response types by the reaction of clotting to exercise it was found that the seasonality of the MDA concentration in the plasma in hyper-and hypocoagulatory groups at rest is similar: in the first group its values in spring and summer are significantly higher compared to those in autumn and winter (by 95.2% on average), and in the second group the mentioned value was also at its maximum in spring. The MDA concentration in haemolysate remained virtually unchanged in all the allocated groups throughout the year.       

Exercise caused multidirectional changes of lipid peroxidation indices in blood plasma and haemolysate throughout the year. Thus, in the first, hypercoagulatory, response unit muscular activity led to a reduction in the MDA concentration in the blood plasma during the autumn and spring months (by 38.08% and 25.21%) and its increase during the winter and summer ones (by 10.33% and 17.2%). The MDA concentration in haemolysate also significantly increased in the winter (51.96%) and summer (by 23.8%) time, and to a much greater extent than in the plasma, indicating an increase in the intensity of lipid peroxidation. In the hypocoagulatory response unit changes in the MDA concentration were similar in their direction to the changes found in the hypercoagulatory group, but they were significant only in the spring (25.26% reduction on average) and summer months (21.33% increase on average). The value of this indicator in haemolysate significantly increased only in winter (by 56.51%). In the third, mixed group the MDA concentration in the blood plasma increased by 33.69% and in haemolysate – by 39.09%, under the influence of exercises in the winter time.

During the study of lipid peroxidation processes in the groups different in terms of fibrinolysis systems’ response to the physical load it was found that at relatively rest the MDA concentration in the plasma of persons with the hyperfibrinolytic type of response significantly increases only during the winter-spring transition period (by 2.24 times), in persons of the hypofibrinolytic type this value is also considerably higher in spring compared to the autumn-winter months (by 45.92% and 86.63%), and in the groups of multidirectional changes of fibrinolytic system’s indices its values in the warm seasons (spring-summer) are much higher than those obtained in the autumn-winter period (by 79.83% on average).

Thus, the study of the peroxidation processes in hyper- and hypofibrinolytic response units as well as in the hyper- and hypocoagulatory groups while at rest reveals significantly higher values of the MDA concentration in the blood plasma in the spring season compared to the rest of the year. The MDA concentration in haemolysate remains relatively constant in all the groups throughout the year.

Under the influence of the physical load the MDA concentration in the blood plasma in the first, hyperfibrinolytic response unit decreased only in the autumn months (by 24.73%), and changes of this indicator in haemolysate were multidirectional: muscular activity led to its increase during the autumn-winter period (by 32.3% and 72.25%) and to its decrease in the spring months (by 19.16%). The MDA concentration in the blood plasma in the second, hypofibrinolytic group increased considerably in winter and summer (by 40.16% and 26.75%) as a result of exercise, and in haemolysate this indicator changed only in the winter period when it increased by 45.46%. The post-exercise MDA concentration in thr blood plasma in the third group remained unchanged, and in haemolysate it significantly increased in the winter and summer months (by 37.62% and 37.01%, respectively).  

Conclusion. Regardless of the response groups the observed individuals belong to, a considerable activation of lipid peroxidation processes is observed in the changes of lipid peroxidation indices at rest during the spring period, which is manifested in a significant increase of the MDA concentration in the blood plasma.

Changes of lipid peroxidation indices under physical loads are of the same direction in all the groups: the MDA concentration in the blood plasma decreases in autumn and spring and increases in winter and summer. In haemolysate the most pronounced changes occur in the winter months and are manifested in a significant increase of the mentioned indicator. 

References

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Corresponding author: jakimovalena@mail.ru

Abstract

The article explores seasonality of some lipid peroxidation indices under intensive physical loads. Subject to the study were 33 individuals aged 18.12 ± 0.19 years, 170.2 ± 1.24 cm tall and weighing 63.06 ± 1.13 kg; with 15 of them being tested for malondialdehyde (MDA) concentration as an interim lipid oxidation product (LOP) both in plasma and haemolysate. The tests found the MDA concentration in the blood plasma being indicative of the LOP process intensification over the annual cycle with reduction of the anti-oxidation system functions in the warm season. The intensive muscular activity was found to evoke diverse changes in the MDA concentration in blood plasma and haemolysate, with the MDA level being on the fall in the transitional seasons (autumn and spring time), the decrease being statistically significant only in the spring months; and with the MDA concentration being on the rise in the winter and summer time; moreover, it was also found that the MDA concentration in haemolysate showed significant growth in the autumn and winter time. The study results were interpreted as indicative of the LOP processes being more active in the winter time and somewhat inhibited in the spring time under high-intensity exercise.