Influence of physical activity of racehorses on lactate dehydrogenase and creatine kinase activities, and protein synthesis

Abstract

The aim of the research was to assess the effects of physical activity of various intensity on the degree of damage to certain organs resulting from increased free radical production, as well as the adaptability of the organism to physical exercise. Two groups of healthy 3-5-year-old full-blooded racehorses were assessed. The first one ran a 2400-meter gallop race, which is considered a short-lasting, intense physical activity; lipid status was assessed prior to, and 48 and 72 h after the race. The second group ran a forty-kilometer endurance ride, which is a long-lasting moderate physical activity; the lipid status was assessed immediately before, on finishing and 48, 72, 96, 120 and 144 h after the race. The total activity of LDH changed 72 h and 96 h following the gallop race (p>0.05), whilst the maximum activity was measured immediately after the endurance ride. By means of electrophoresis LDH in all the horses 5 isoforms were detected. The activity of LDH1 72 h after the gallop race significantly rose in comparison to the one before the race (p lt 0.05), whilst the activity of all other isoenzymes, LDH2-LDH5, did not change significantly (p>0.05). Following the endurance ride LDH1 activity rose at all sampling times, reaching the maximum at 96 h and 144 h in comparison to the values both before and on finishing the ride (p lt 0.01). The increase in the activity of LDH2 was significantly higher 48 h, 72 h, 96 h and 120 h (p lt 0.05) after the race in comparison to that before the race, and at 48 h, 72 h, 96 h, 120 h and 144 h (p lt 0.05) in comparison to the values on finishing the race. LDH3 activity significantly decreased and LDH5 rose immediately after the endurance ride (p lt 0.01), whilst LDH4 significantly rose at all times following the endurance ride (p lt 0.01). The CK activity pointed to high, medium and low degree of adaptation of horses to physical activity. The concentrations of total proteins, albumins and globulins remained within the physiological range at all sampling times, with the exception of 96 h after the endurance ride, when the fall in albumin concentration was significant (p lt 0.01). Long-lasting physical activity of low intensity leads to cellular damage in the myocardium, muscles, liver and to hypoalbuminaemia, which is a consequence of free radical production.

Cilj rada je bio utvrđivanje efekata fizičkog opterećenja različitog intenziteta na stepen oštećenja ćelija pojedinih organa usled pojačane produkcije slobodnih radikala, kao i adaptiranosti organizma na fizičko opterećenje. U ispitivanju su učestvovali zdravi punokrvni trkački konji, starosti 3-5 godina, podeljeni u dve grupe. Prva grupa je podvrgnuta kratkotrajnom fizičkom opterećenju visokog intenziteta tokom galopske trke na 2400 m, a ispitivani parametri su određivani pre trke, 48 h i 72 h posle trke. Druga grupa je bila podvrgnuta prolongiranom fizičkom opterećenju niskog intenziteta tokom endjurans trke na 40 km, a ispitivani parametri su određivani pre trke, neposredno nakon trke, 48 h, 72 h, 96 h, 120 h i 144 h posle trke. Ukupna aktivnost LDH se menjala 72 h i 96 h nakon galopske trke (p>0,05), dok najveću aktivnost dostiže neposredno nakon endjurans trke. Elektroforetskim razdvajanjem LDH kod svih ispitivanih konja ustanovljeno je 5 izoformi. Aktivnost LDH1 72 h nakon galopske trke se značajno povećala u odnosu na aktivnost pre trke (p lt 0,05), dok se aktivnost ostalih izoenzimskih oblika, LDH2-LDH5, nije statistički značajno razlikovala (p>0.05). Nakon endjuransa uočen je porast aktivnosti LDH1 u svim ispitivanim vremenskim intervalima, sa maksimalnom aktivnošću 96 h i 144 h u odnosu na period pre i neposredno posle trke (p lt 0.01). Porast aktivnosti LDH2 je bio statistički značajno veći 48 h, 72 h, 96 h i 120 h (p lt 0,05) u poređenju sa vrednostima pre trke i 48 h, 72 h, 96 h, 120 h i 144 h (p lt 0,05) u odnosu na vrednost neposredno posle trke. Aktivnosti izoforme LDH3 ispoljava statistički značajan pad, a LDH5 povećanje neposredno nakon endjuransa (p lt 0,01), dok LDH4 značajno raste u svim ispitivanim vremenskim intervalima posle endjuransa (p lt 0,01). Aktivnost CK je imala visoki, srednji i nizak stepen adaptiranosti konja na opterećenje. Koncentracija ukupnih proteina, albumina i globulina se u svim analiziranim intervalima kretala u fiziološkim granicama, izuzev endjuransa kada je ustanovljen statistički značajan pad koncentracije albumina 96 h nakon trke (p lt 0,01). Prolongirano fizičko opterećenje niskog intenziteta dovodi do oštećenja ćelija miokarda, mišićnog tkiva, hepatocita i hipoalbuminemije kao posledice stvaranja slobodnih radikala.