Document Type : Original Article
Authors
1 Pediatric Urology and Regenerative Medicine Research Center, Children Medical Center, Tehran University of Medical Sciences, Tehran, Iran
2 Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
3 Department of Pathology, Isfahan Kidney Diseases Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
4 Iran Telecommunication Research Center, Tehran, Iran
Abstract
Graphical Abstract
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Highlights
Keywords
Main Subjects
Introduction
Urinary tract stones or Urolithiasis such as kidney stones are small, dense, and solid particles that are constituted in one or both kidneys and occasionally are conveyed to the ureters. Urinary stones may warry from a sand grain to a small ball in terms of their size and could be solitary or multiple. Urolithiasis generally involves adults older than 20 in both genders; however, it is more common in males. Calculi evacuation causes severe and torturous pain in a few minute intervals. The pain initially emerges in the posterior lower border of the ribs; subsequently, bypassing the stone through the ureter, the pain immigrates to the inguinal area. Once the stone is eliminated, the pain stops; although, a non-evacuating and stable calculus presents no symptoms (1, 2). Different conditions are considered the main triggers of Urolithiasis including dehydration, salt overuse, hyperparathyroidism, gout, urinary obstruction, chronic kidney infection, and irregular voiding habits (3-5).
There are various types of factors predisposing the urinary system to develop stones; the risk factors could be divided into two major groups modifiable and non-modifiable. Certain biochemical abnormalities of the urine composition have been associated with an elevated risk for urolithiasis. These include higher urine calcium, lower urine citrate, higher urine oxalate, higher urine uric acid, and lower urine volume (6-8). Dietary factors can play a pivotal role in promoting stone formation, initially by affecting the urine composition. Diminished intake of fluid, calcium, potassium, and phytate and a greater intake of oxalate, sodium, sucrose, vitamin C, and possibly a proportion of proteins have collaborated with an increased risk for kidney stone formation (9-13). Numerous drug consumption has been related to an enhanced risk of kidney stone formation. Some drugs like topiramate, acetazolamide, and long-term glucocorticoids can promote kidney stone formation by inducing metabolic abnormalities that alter the urine composition (14, 15). Since the metabolites of ethylene glycol can induce hyperoxaluria and calcium oxalate stones (16), for the development of a model of calcium-based renal calculi, ethylene glycol is the most commonly utilized agent in the experiments (17).
Based on the growing statistics of Urolithiasis, unceasingly various etiologies are investigated the cell phone waves could be mentioned among these. Electromagnetic Radiation (ER) refers to the waves of the electromagnetic spectrum, propagating through space, carrying electromagnetic radiant energy. It is classified by a frequency that includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays (18). These waves have a variety of applications in the life-related daily routine utilized devices and systems including refrigerators, televisions, radios, copy machines, computer screeners, halogen lamps, and printers (19).
The increasing use of cell phones and numerous reports in recent years about abnormality developing effects of these waves on different processes of growth gave rise to concerns in terms of their harmful effects on human health. Currently, a great deal of evidence was revealed some of these critical non-thermal consequences such as cell function alteration, decrease in melatonin production, changes in electroencephalogram results, and gene expression patterns (20-26).
To the best of our knowledge, no study was implemented to investigate the influence of cell phone radiations on urolithiasis and the parameters related to the size, type, and location of the stones. Therefore, the present study was conducted on a rat model to address the aforementioned issue. We hope our findings open a novel path to the further understanding and treatment of urinary tract calculi.
Methods
Animals and Ethical Approval
Forty, 4 to 6-week-old, Wistar rats weighing 200±10 g were purchased and all of them are healthy. All rats were housed and caged in the animal facility at the Urology Research Center of Sina Hospital under an approved Tehran University of Medical Sciences ethics committee protocol) IR.TUMS.VCR.REC.1398.680(. Regarding the environmental conditions, the average temperature and humidity were 24±1ºC and 50-55 percent, respectively; with a 12-h light-dark cycle. A mixture of 43 percent of vegetable proteins and grains consisted of the animal's chow.
Ethylene glycol with a purity of ≥99.5% was obtained from Sigma-Aldrich incorporation (Darmstadt, Germany). To generate cellphone waves, we used a wave transmitter with a wavelength equal to existing cellphones in the usual markets. At the time of wave transmission, the cages were entered in an aluminum box with just one open side to prevent the egression of waves (Figure 1).
Figure 1. A: Phone on the side of the rat cage. B: Electric field at 885 MHz-phone on the side.
This study evaluated the possible toxicological effects of exposure to 885 MHz Global System for Mobile Communications (GSM) like radiofrequency radiation (RFR) on the histology and ultrastructure of various body tissues of Wistar rats. Rats were exposed to FRF 12 times a day, each time 10 minutes for a month at a whole-body specific absorption rate (SAR) of 0.90 Watt/kg.
Animal Grouping and the Modeling Method
After a one-week acclimatization period, the rats were randomly allocated into 4 groups using a computer-generated randomization list: Group A served as the control group in which rats experienced no exposure; Group B was ethylene glycol receivers in which a daily amount of 3cc ethylene glycol was added to their diurnal 500cc drinking water; Group C acted as the wave exposure group in which rats underwent electromagnetic waves radiation for 12 times a day, 10 minutes each; finally Group D represented the associated exposure of waves and ethylene glycol as the above-mentioned routes. Before any intervention, 1 male and 1 female rat were randomly selected from each group to perform a CT-Scan to ensure there was no evidence of stones. Each group contained 5 male and 5 female rats. The rats of each group were stained and numbered with the yellow color of Picric acid in different parts of their bodies (head, foot, right hand, and the waist for groups A, B, C, and D, respectively). The period dedicated to all groups of animals' experimentations was 1 month.
Serum Analysis
Blood samples were collected from each rat, and the serum urea, uric acid, creatinine, calcium, phosphorus, and total protein levels were measured and compared to each other.
Radiologic Analysis
After the 4 weeks, 4 animals (2 males, 2 females) were randomly selected from each group and were anesthetized by 2% Xylazine and 5% ketamine. Afterward, the rats were placed in the supine position on the LOTUS-in Vivo Micro-CT (Advanced Medical Technologies & Equipment Institute, Tehran University of medical sciences, Tehran, Iran) table (as shown in Figure 2). Different radiographic images were captured in coronal and transverse planes.
Figure 2. The rats positioning on the LOTUS-in Vivo Micro-CT table.
Pathological Examinations
For further pathologic examinations of the urinary system, 2 rats, including a male and a female, were randomly selected from each group and were sacrificed. Their urinary system including kidneys, ureters, bladder, and urethra was sent to the pathology center of Sina hospital of Tehran University of Medical Sciences for H&E staining, histopathologic examinations, and further outcomes of the experiment. Other organs of those rats were applied in other ongoing studies in the same facility.
Results
Serum Parameters
In serum specimens of the waves + ethylene glycol group, there was a significant difference in urea, uric acid, and creatinine compared to the control group in both genders; besides, a meaningful increment was seen in the level of phosphorus of female rats. The serum level of urea in the same group experienced a notable rise, regardless of gender, in comparison to rats of the ethylene glycol group. However, in the same comparative setting, just male rats met the level of significance for uric acid and creatinine levels. The results are detailed in Tables 1 and 2.
Table 1. Serum parameters value in wave ethylene and control groups of the study
|
Serological Parameters |
Waves Ethylene Group |
Control Group |
P-value* |
P-value** |
||
|
Female |
Male |
Female |
Male |
|||
|
Urea |
71±3.8 |
70±3.6 |
64.5±2.3 |
67.5±3.2 |
<0.001 |
<0.001 |
|
Uric Acid |
93.5±3.3 |
95±4 |
31.09±1.3 |
23.15±1 |
<0.001 |
<0.001 |
|
Creatinine |
8±0.9 |
6.5±0.3 |
31.23±1.4 |
56.09±2.9 |
<0.001 |
<0.001 |
|
Total protein |
7.5±0.5 |
8.4±1 |
8±0.9 |
7.02±0.5 |
0.876 |
0.946 |
|
Calcium |
36±1.6 |
37±1.7 |
10.5±1 |
10.7±1.1 |
0.884 |
0.665 |
|
Phosphoric |
19±1.6 |
19.5±1.7 |
14.2±2.3 |
10.6±1.1 |
0.001 |
<0.001 |
* Female in Waves Ethylene group vs. Control group ** Male in Waves Ethylene group vs. Control group
Table 2. Serum parameters value in wave + ethylene glycol and ethylene glycol groups of the study
|
Serological Parameters |
Waves Ethylene Group |
Ethylene Group |
P-value* |
P-value** |
||
|
|
Female |
Female |
Female |
Male |
||
|
Urea |
71±3.8 |
60±1.5 |
60±1.5 |
67±3 |
<0.001 |
0.001 |
|
Uric Acid |
93.5±3.3 |
86±4 |
86±4 |
93.03±4.6 |
0.048 |
0.032 |
|
Creatinine |
8±0.9 |
7±0.5 |
7±0.5 |
5.36±0.4 |
0.061 |
<0.001 |
|
Total Protein |
7.5±0.5 |
7.05±0.6 |
7.05±0.6 |
7.01±0.5 |
0.233 |
0.911 |
|
Calcium |
36±1.6 |
34±1.4 |
34±1.4 |
36.18±1.7 |
0.068 |
0.057 |
|
Phosphoric |
19±1.6 |
17±2.4 |
17±2.4 |
18.9±2.9 |
0.159 |
0.291 |
* Female in Waves Ethylene group vs. Ethylene group ** Male in Waves Ethylene group vs. Control group
Radiologic Outcomes
The CT scan results confirmed the formation of stones in the receivers of the ethylene glycol; while, there was no evidence of calculi in the control group. At the end of the trial, by evaluating the results of the radiologic examinations in the rats of simultaneous treatment with ethylene glycol and mobile waves, the size of stones was either undetectable or extremely small; however, the findings of radiologic examinations were unreliable and not led to a definite and meaningful conclusion.
Pathologic outcomes
The findings of the pathologic examinations were presented in Figures 3 and 4. Evaluation of slides provided from the kidneys of the ethylene glycol group compared to normal tissue demonstrated hemorrhage in Bowman's capsule and glomeruli size decrement. Although the aforementioned changes were present in the mice of simultaneous exposure of waves and ethylene glycol, the extent of them was much less in this group. Lymphocytic cell ratio increased in comparison to other groups; additionally, epithelial cell death of Bowman's capsule wall was seen. In the central section of the tissues, the number of cells in the proximal and distal convoluted tubules was indeterminate, indicating the cell structure alterations. Also, the examinations revealed that there were calculi in the ethylene glycol group, independent of gender, which was greater in magnitude on the left side and had higher levels of inflammation.
Figure 3. The histopathologic examination of the kidney. (A, B) Control group; (C, D) ethylene group; (E, F) mobile waves; (G, H) ethylene glycol + mobile waves.
Results of the Group C and D histopathologic investigations exhibited that the size and number of stones in these groups were diminished; however, the calculi still were seen in these groups and not removed. Other structural impairments including Bowman's capsule wall cell death and interstitial lymphocytes infiltration were slighter in these groups. The presence of cell membranes in distal convoluted tubules was more evident than in proximal convoluted tubules. The epithelial membrane of collecting ducts in the renal medulla was subjected to no changes and remained intact.
Figure 4. The histopathologic examination of the bladder. (A) Control group; (B) ethylene group; (C) mobile waves; (D) ethylene glycol + mobile waves.
Discussion
The primitive attempts regarding the noninvasive elimination of kidney stones were performed in Munich in 1972 (27). Following the numerous in-vitro investigations and animal trials, in 1980 a complete revolution emerged and the widely known procedure, ESWL, was clinically introduced to disintegrate the urinary tract stones (28-30). This technique thereupon gained worldwide attention and was widely used in the management of patients suffering from urinary tract stones (31). Despite the wide range of yielded benefits, a minor, but slightly serious, series of disadvantages including damage to proximal structures, bleeding, inflammation, perforation, and cardiac arrhythmias exist. Also, it is contraindicated in pregnancy and coagulopathies (32-34).
Over the recent years, along with the drastic progress in the territory of telecommunication, the application of cell phones has become a necessity. This improvement had plenty of advantages for the users; however, the other side of the new era still stays in the shadow. A wide array of studies has been implemented to identify the impact of electromagnetic waves on different organs; nevertheless, it remains inconclusive (23). On the other hand, to find out whether the favorable effects of mobile waves on the body exist, we compared the rate of ethylene glycol-induced urolithiasis in the rats exposed to these waves and non-exposed ones.
In this study, we examined the effects of mobile waves on the urinary system stones induced by ethylene glycol in Wistar rats. The presence of urolithiasis in the rats who received ethylene glycol has been proved by CT Scan, and multiple calculi have been formed in this group. In one of the experimental groups of our study, besides the treatment with the stone-forming agent, the rats experienced contact with the electromagnetic waves emitted from cell phones, the mankind regularly is in touch. Surprisingly a considerable amount of calculi disappeared, demonstrating the effectiveness of commonly used handheld devices in one of the most pain-causing conditions of the urinary system.
To extend our knowledge, this is the first report of mobile waves utilization in pulverizing urinary tract stones. Recognition of this study's limitations will be helpful in the future investigation's design and implementations; those include a lack of determination of the stones' size and the minimum dimensions of the stones of which these waves can fragment and the inability to employ human subjects instead of animals and the small sample size.
Conclusion
From the findings of our study regarding the short-term exposure of rats to waves emitted from mobile waves, we conclude that cell phone electromagnetic waves had a remarkable disintegrating effect on urolithiasis and the rate of detected stones and destructive pathological outcomes resulting from urinary tract calculi were notably diminished. Despite the beneficial impact of these waves in this study, to confirm the aforementioned results further investigations are needed.
Author’s contributions
VAY was the principal investigator, AN wrote the manuscript, RM and NN run the project and laboratory tests, LZ analyzed the data, and DT edited the manuscript
Acknowledgments
Special thanks to the Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Conflict of interest
The authors declare that there is no conflict of interest.
Funding
The authors received no financial support for this research.
Ethical statement
Approved by Tehran University of Medical Sciences ethics committee protocol) IR.TUMS.VCR.REC.1398.680(.
Data availability
Data will be provided by the corresponding author on request.
Abbreviations
CT Computed tomography
ESWL Extracorporeal shock wave lithotripsy
RF-EMW Radiofrequency electromagnetic wave of cell phones
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