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Aim: The aim of this study was to evaluate any measurable change in antioxidant and free radical scavenger status in periodontal disease. Methods and Materials: A total of forty subjects consisting of 20 test subjects (10 males and 10 females) and 20 (10 males and 10 females) controls were recruited for the study. The antioxidant defence status in serum (in terms of Superoxide dismutase, Glutathione peroxidase (GSHPx) & Catalase), serum lipid peroxidation (in terms of Malondialdehyde) and free radical scavengers (Vit C) was assessed.
Results: A significant difference was noted between tests and controls. Negative correlation was seen between the values of Lipid peroxidation & that of SOD, GSHPx & Catalase. Our study confirms that lowered level of SOD, Catalase & GSHPx is associated with hyper lipid peroxidation in periodontal disease.
Key words: Reactive oxygen species, periodontal disease, Lipid peroxidation and Vit C.
Periodontitis, an inflammatory disorder of the periodontium, damages the bone and connective tissue that supports the teeth. The severity of periodontitis is characterized by the degree of marginal bone loss, the depth of periodontal pockets, the degree of attachment loss and the number of teeth with furcation development1.
It has been observed that various invading bacteria trigger the release of cytokines such as interleukin 8 and tumor necrosis factor-Î±, leading to elevated numbers and activity of polymorphonucleocytes (PMN). As a result of stimulation by bacterial antigens, PMN produce the reactive oxygen species (ROS) superoxide via the respiratory burst as part of the host response to infection. Patients with periodontal disease display increased PMN number and activity. It has been suggested that this proliferation results in a high degree of ROS release, culminating in heightened oxidative damage to gingival tissue, periodontal ligament and alveolar bone.
The human body does contain an array of antioxidant defense mechanisms (non-enzymatic and enzymatic antioxidants) to remove harmful ROS as soon as they are formed and to prevent their deleterious effects2. The non-enzymatic antioxidants include vitamins E and C, and reduced glutathione (GSH), while the enzymatic antioxidants include superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPx).In recent years, more attention has been focused on the role of reactive oxygen species, lipid peroxidation products and antioxidant systems in the pathology of periodontitis. Recent medical and dental research in this area is geared towards the prevention of free radical-mediated diseases by using specific nutrient antioxidants3.
MATERIALS & METHODS
The present study was conducted in the department of Periodontics, HIDS, Paonta Sahib,H.P.(India), with the objective to evaluate any measurable change in antioxidant and free radical scavenger status in periodontal disease. A total of forty subjects (aged 20-50 years) consisting of 20 test subjects (10 males and 10Females) and 20 (10 males and 10 females) controls were recruited for the study. Subjects with history of antioxidant therapy & with current infections and other disease (other than periodontal) were excluded from the study. Subjects and controls were not engage in tobacco smoking or chewing, or alcohol consumption, and did not suffer from any systemic diseases and had similar dietary habits. The severity of the periodontitis was diagnosed by measuring the periodontal pocket depth (>5mm), and gingival recession (Grade III).
Blood samples were obtained by venous arm puncture and collected in heparinized tubes and following tests were conducted.
Methods for serum levels:
Estimation of serum lipid peroxidation [in terms of Malondialdehyde,(MDA)] (Yagi et al method, 1976)4
Estimation of superoxide dismutase (SOD) (Marklund & Marklund, 1974)5
Estimation of Catalase (Aebi et al, 1983)6
Estimation of glutathione peroxidase (GSHPx) (Rotruck et al, 1973)7
Estimation of Vit C (Omaye et al, 1971)8
Numerical data was expressed as Mean Â± SD & student 't' test was applied and P â€¹ 0.01 was regarded as highly significant. Table 1 represents the serum lipid peroxidation (MDA), plasma MDA levels were significantly higher in test subjects as compared to control. In test subjects, male has plasma MDA (n moles/dl) 310Â±72, female 306Â±45 where as in control group value are 208.8Â±21.5 and 180Â±22.5 for males and females respectively.
Table 2 assess the antioxidant defence status in serum (in term of Superoxidase dismutase, GSHPx and Catalase). SOD levels were significantly lower in test group than in healthy control. The numerical values of SOD in U/mgHb for males is (2.1Â±0.2), females (1.6Â±0.4) as compared to healthy males (3.15Â±0.25) and females (3.1Â±0.25).
Table 3 shows that there is significant reduction in level of vit C in test as compared to control. The level of vit C (Âµ mol/L) in test group, male is 35Â±5 and female is 30Â±4 and control have values male (52Â±5) and female (50Â±4).
Reactive oxygen species (ROS) are produced in animals and humans under various physiological and pathological conditions. ROS are produced continuously in living cells as byproducts of normal metabolism, during the metabolism of xenobiotics, and during exposure to high temperature or radiation. They also form due to the leakage of electrons from electron transport chains and the generation of superoxide or hydrogen peroxide by peroxisomal enzymes2. Deliberate generation of free radicals occurs during phagocytosis as part of the bactericidal reaction 9. ROS are also produced by phagocytes to destroy microorganisms.
Antioxidants are present in all body fluids and tissues, and protect against endogenously-formed free radicals, usually produced by leakage of the electron transport system10. Antioxidant enzymes such as superoxide dismutase and glutathione peroxidase provide protection within cells whilst low-molecular-weight scavenging antioxidants are present in extracellular fluid. These include ascorbic acid, Î±-tocopherol and Î²-carotene. In addition, dietary-derived components such as uric acid, non-protein thiols and glutathione also act as antioxidants 10,11, as does albumin found in plasma and saliva 12,13. Ascorbic acid is believed to be the major aqueous antioxidant, whilst Î±-tocopherol protects against lipid peroxidation14.
In the present study we have tried to assess free radical scavengers (Vit. C), serum lipid peroxidation (in terms of Malondialdehyde),the antioxidant defence status in serum ( in terms of Superoxide dismutase, GSHPx & Catalase) in patients with periodontal disease and controls.
In chronic periodontitis, progressive generation of free radicals takes place leading to increased lipid peroxidation and decrease in antioxidant enzyme defence status .Our study confirms that lowered level of SOD, Catalase & GSHPx is associated with hyper lipid peroxidation in periodontal disease. Free radical-induced tissue injury has been demonstrated to be increased in individuals with periodontitis15. Enhanced lipid peroxidation was reported in the periodontal tissues of cats with gingivitis16. Gutteridge17 reported that the extent of tissue damage could be assessed by measuring the concentrations of lipid peroxidation products and antioxidants.
In Periodontal disease there is an increase in MDA levels due to increase in oxidative stress, production of reactive oxygen species. Increased oxidative stress releases certain compounds from the tissue membrane which activate polynuclear leukocytes to release more free radicals 3.
Free radical scavenger such as Vit C is lowered in patients than in controls. Vitamin C is a powerful reducing agent and an important water-soluble vitamin for humans and certain other animals. It has been shown to scavenge superoxide radicals, hydrogen peroxide, and singlet oxygen. Vitamin C also protects plasma lipids against lipid peroxidation and has an important role in the regeneration of Î±-tocopherol18.
Enhanced oxidative stress in cells results in the activation of free radical scavenging enzymes to neutralize the toxic effect of ROS. Superoxide dismutase and Catalase respectively protect the cell against ROS by scavenging superoxide radicals and hydrogen peroxide, which cause damage to the structure and function of membrane assembly 19. Glutathione peroxidases are major enzymes that remove hydrogen peroxide generated by SOD in the cytosol and mitochondria by oxidizing reduced glutathione (GSH) to its oxidized form (GSSH). Glutathione and glutathione peroxidase have been documented to have regulatory effects on cell proliferation20. Increased plasma GSHPx activity has been reported as an indirect indicator of oxidative stress 21. It was also reported that reduced glutathione effectively protects vital cell components from structural damage during hyper-inflammation 1, 22.
We thus conclude that the disturbance in the endogenous antioxidant defense system due to the over-production of lipid peroxidation products at inflammatory sites can be related to a greater degree of oxidative stress in patients with periodontitis
Periodontal disease is clearly an important and potentially life-threatening condition, often underestimated by health professionals and the general population. The concept on the role of free radicals in the initiation and progression of periodontal disease points to the purposefulness of including bioxidants and other bioregulatory substances in the pharmacological prevention of these diseases. It is now of importance to determine the possible contribution of diet to salivary antioxidant status. In the future antioxidant supplementation may be used in the treatment or prevention of these chronic diseases of the oral cavity.
TABLE 1 LIPID PEROXIDATION
PLASMA MDA (n moles/dl)
310 Â± 72
306 Â± 45
208.8 Â± 21.5
TABLE 2 ANTIOXIDENT DEFENCE STATUSES
SOD (U/mg Hb)
21 Â± 0.2
1.6 Â± 0.4
3.15 Â± 0.25
4.1 Â± 0.3
3.9 Â± 0.4
4.3 Â± 0.3
GSHPx (Âµg OF GSH utilized/ mgHb/min)
3.6 Â± 0.28
2.1 Â± 0.3
5.7 Â± 0.23
TABLE 3 FREE RADICAL SCAVENGER ACTIVITIES
VIT C (Âµmole/L)
35 Â± 5
30 Â± 4
52 Â± 5