Comparative Study Of Oxidative Stress And Antioxidant Activity In Males And Females With Increase In AgeCorrespondence Address :
*Asst Professor Department of Physiology, Adesh Institute of Medical Sciences and Research,Bathinda-151101, Punjab,[India] E-mail email@example.com. Tel: +91-9876010729
Aim:The aim of the study was to compare the extent of free radical damage in the form of oxidative stress and the antioxidant activity with increase in age in healthy males and females.
Methods: The present study was conducted in 150 normal healthy subjects of both sexes in the age ranging from 15 â€“ 65 years. They were divided in 3 groups. Each group had equal number of male and female subjects. Oxidative stress was by measured by estimating malondialdehyde [MDA], a lipid peroxidation product, and antioxidants in the form of superoxide dismutase [SOD] and glutathione peroxidase [GPX] in both male and female subjects of all age groups.
Results: MDA levels increased significantly with increase in age of all subjects and this increase was more in females was more than males of each group. Levels of antioxidant enzymes [SOD and GPX] decreased with increase in age more in males than females of each group.
Conclusion: Males are exposed to greater risk of oxidative stress with age compared to females which may be related to lower life expectancy in males.
Lipid Peroxidation, MDA, SOD
Life span of an organism depends on itâ€™s ability to counteract oxidative threat (1). Free radicals are generated by redox reactions that occur during normal physiological processes and also contributed by environmental sources, cause cell damage by autocatalytic lipid peroxidation of membranes, lesions in DNA, and cross-linkage in proteins.(2) All the major classes of biomolecules may be attacked by free radicals but the lipids are probably the most susceptible (3). Cell membranes are rich sources of polyunsaturated fatty acids [PUFAs] which are readily attacked by oxidizing radicals. The oxidative destruction of PUFAs, known as lipid peroxidation is particularly damaging because it proceeds a self perpetuating chain reaction4. Malondialdehyde,[ MDA] is the major reactive aldehyde, resulting from the peroxidation of biological membrane5. Detoxification of reactive oxygen species is one of the prerequisites of aerobic life, and many defenses have evolved providing an important antioxidant defense system of prevention, interception and repair. These defenses consist of nonenzymatic scavengers and quenchers as well as enzymatic systems including superoxide dismutases[SOD] and hydroxyperoxidases such as catalase and glutathione peroxidase. Oxidative stress results from the imbalance in the pro-oxidant antioxidant equilibrium in favour of pro-oxidants and is apparent in pathology associated with aging and many age-related chronic diseases such as diabetes mellitus, rheumatoid arthritis and neurodegenerative diseases (6). In this study an effort was done to compare oxidative stress in males and females . To assess the level of oxidative stress malondialdehyde, the end product of lipid peroxidation reaction that is produced as a result of damage to cell membrane lipids by free radicals was measured. To determine the extent of protection against these oxidants, the levels of antioxidants SOD and GPX were estimated in the serum and plasma of all subjects.
The present study was conducted in 150 normal healthy individuals of different age-groups. The study was conducted in department of Physiology Adesh Institute of Medical Sciences and Research, Bathinda in department of Physiology with approval of ethical committee. The attendants of the patients in the hospital were taken as subjects. They were divided into three Groups on the basis of age; Group I [15-30 years], Group II [31-45 years] and Group III [46-65 years]. Each group comprised of 50 subjects and equal number of males and females were taken in each group. Informed consent was taken from all the subjects. A detailed history including the history of diet and lifestyle was taken and general physical and systemic examination was done .All the selected subjects were healthy and were not suffering from any disease like hypertension, diabetes mellitus, rheumatoid arthritis, malignancy, collagen disorders, or any other disease. Pregnant females and subjects on any medication or taking vitamins or mineral supplements were excluded from study. Weight was taken on a weighing scale with standard minimum clothing to the nearest 0.5 kg. Hemoglobin was estimated by using Sahliâ€™s method (7).
For assessment of other parameters 10 ml of fasting venous blood samples was taken under with dry disposable syringe and needle under all aseptic conditions by venepuncture in the anticubital vein in a sterile, dry, acid washed vials. Malondialdehyde [MDA] levels in serum were estimated by the method of Satoh (8). Superoxide Dismutase [SOD] activity in serum was assayed by using the method of Marklund and Marklund (9) Glutathione peroxidase [GPX], GPX activity in plasma was measured by using hydrogen peroxide as a substrate by applying the method of Rotruck. (10)
Statistical analysis: Statistical analysis was carried out by Studentâ€™s paired â€˜tâ€™-test. The data were expressed as Mean Â± SD and the p value < 0.05 was taken as significant.
The subjects were divided into three groups [Group I, Group II and Group III ] on the basis of age. Each Group comprised of 33.3% of the total subjects with equal no of males and females.[Table /Fig 2] depicts that mean Â± SD serum MDA levels in males and females increased with age but levels in males were more than the females of same age group. Highly significant p<0.001 percentage difference was observed between males and females of Group II . Mean Â± SD serum SOD levels decreased in all subjects with increase in age Males of Groups I & II had significantly lower values than the females of same age
groups, while serum SOD levels in males of Group III was significantly higher than females of same age Group. Mean Â± SD serum GPx levels also decreased with increase in age and levels in males were less as compared to females in each group.
Malondialdehyde [MDA], a secondary product of lipid peroxidation, used as an indicator of tissue damage by a series of chain reactions(11). In this study we observed that the levels of MDA increased with increase in age and levels in males were significantly more as compared to females.in each group. A significant increase in lipid peroxidation level was also observed by several other authors in elderly subjects as compared to younger subjects.[12,13,]. Increase in serum lipid peroxidation level with increase in age is linked to increase in the cellular amount of free radicals by generation of superoxide radicals and hydrogen peroxide from respiring mitochondrias(14). Alteration in lipid peroxidation and antioxidant enzymes was done in population of Amritsar, India (15). Increases in the body content of iron with age [in men throughout their lives and in women after menopause] in humans, may increase the risk of oxidative damage.(16).
. In our study the mean SD lipid peroxidation level in males was more as compared to females. Similar results showing male subjects having significantly higher values as compared to female subjects were observed in another study (17). Accumulation of chromolipids which result from the polymerization of oxidized unsaturated lipids increase lipid peroxide levels in aging Females are endowed with the system of inhibiting lipid peroxide production or accelerating itâ€™s removal by mechanisms different from that of male which accounts for lower levels of lipid peroxides in females(18).
Decline in the competence of the oxy radical-detoxifying mechanisms, with increase in age results in increased serum lipid peroxidation (19) In our study serum SOD levels and plasma GPX levels decreased in all subjects with increase in age Similar reports of decreased antioxidant enzyme activities with increase in age has been reported in by other authors [ 20, 21].
In present study ,males had lower SOD and GPX values than the females of same age groups Superoxide dismutase [SOD] is the first line of defense against superoxide radical. SOD is considered to be a stress protein which is synthesized in response to oxidative stress which is involved in pathophysiology of aging and age-related diseases (22). CuZn superoxide dismutase activity in males was less than females (23). Increase in SOD activity in females as compared to males was correlated with greater longevity in females (24). Similar reports of lower E-GPX activity in men. than women was found in another study (25). It is well reported that low activity of this enzyme may render the tissue more susceptible to lipid peroxidation damage (26) Glutathione peroxidase is a selenoenzyme which catalyzes the reduction of hydroperoxides at the expense of reduced glutathione GPX catalyses the reduction of variety of hydrogen peroxide [ROOH and H2O2] using glutathione as a substrate, thereby protecting mammalian cells against oxidative stress (27).
It is evident from this study that there is enhanced oxidative stress and decreased antioxidant defence in all subjects with increase in age which can play an important role in the pathogenesis of the various age related diseases .Higher oxidative stress in in males may be the underlying mechanism for the increased rate of ageing and lower life expectancy in males Healthy lifestyle and exercise must be advised and alcohol and smoking should be strictly prohibited in males. . Antioxidants in the form of vitamins/minerals can be given as supplements to counteract changes due to aging
Armstrong D, Sohal RS, Cutler RG, Slater TF, editor. Free radicals in molecular biology, aging and disease. New York, Raven Press. 235-266 .
- Emerging Sources Citation Index (Web of Science, thomsonreuters)
- Index Copernicus ICV 2017: 134.54
- Academic Search Complete Database
- Directory of Open Access Journals (DOAJ)
- Google Scholar
- HINARI Access to Research in Health Programme
- Indian Science Abstracts (ISA)
- Journal seek Database
- Popline (reproductive health literature)