Abstract Normal male
Abstract
Normal male (33) of Swiss albino mice at 9 weeks of age and body weight 41-49gm were the targets for this experimental study. These targeted mice were divided into three targeted groups (n=11each). The first targeted group of mice was kept as unirradiated control. Whereas both second and third targeted groups of mice were used as irradiated groups with laser. Our presented work was considered as a hypothesis that established possible effects of soft laser on the cellular composition of the normal thymus gland in mice. The results of our work proved the hypothesis and the laser caused marked alterations in the cellular composition of the thymus gland especially the composition of the thymocytes which included increased size of the thymocytes and multiplication of the cellular nuclei. These alterations were abundant in the composition of the thymocytes of the thymus glands of the second group of mice irradiated with laser, but the mentioned alterations were more abundant in the composition of the thymocytes of the thymus glands of the third group of mice irradiated with laser.
Key Words: Laser in medicine, Thymocytes of the thymus gland, Histological alterations, Mice.
Introduction
The thymus is located in the mediastinum (1, 2). It has a structure of two lobes which are divided into many lobules and each of them is separated from another by trabeculae that consist of connective tissue. Each lobule comprises two major compartments, an outer cortex and an inner medulla (3). Both cortex and medulla meet at region called corticomedullary junction (CMJ) which considered as the point of entry and exit for developing thymocytes (4). T cell precursors come into existence in the bone marrow and circulating from the bone marrow to violate the thymus by the corticomedullary junction, and during the intrathymic journey the T cells are termed thymocytes (5-8). Inside the thymus and during the development, maturing thymocytes move from the cortex to the medulla (9-11). It should not be ignored that the thymus is able to generate T cells during the life span (12, 13). Besides the greater composition of thymocytes, the microenvironment of the thymus includes different types of thymic epithelial cells (TEC), stroma cells, macrophages, fibroblasts and dendritic cells. All these mentioned cells participate, in one way or the other, in the process of thymocyte maturation (3).
In the medulla of the thymus, there are thymic (Hassall) corpuscles which have variable size and contain large aggregates of thymic epithelial cells (TECs). These cells secrete many cytokines important for the control of the activity of dendritic cells and for the differentiation of regulatory T cells (2).
Laser phototherapy has a main role in the medical fields including: promoting wound healing, tissue repair and prevention of tissue death, relief of inflammation in chronic diseases and injuries with its associated pain and edema, relief of neurogenic pain and some neurological problems (14).
The purpose of this experimental study was to address the question of whether the soft laser could affect the cellular composition of the thymus gland especially thymocyte. In reality, the presented work is a hypothesis needs to be proved.
Statistical factors
Mean: The average pixel value taken to be equal to the average brightness or intensity and computed using equation (1), 18:
(1)
Where M, N are the dimensions of image and I(x,y) is the pixel intensity value (0-255 for a 256 bit image).
Variance: Coefficient of variance is defined as the ratio of standard deviation to the mean and calculated from following equation 18:
(2)
Sometime Cv is assumed as a measure to difference in digital image.
Standard deviation (Std): The Standard Deviation is the most commonly used index of variability and is a measure related to the average distance of the scores from their mean value. This is also an indicator of contrast in the image. It is computed using the following result 18:
(3)
The standard deviation is important in identifying the `details content in an image.
Materials & Methods
33 normal male of Swiss albino mice at 9 weeks of age and body weight 41-49gm were selected to be the targets for this experimental work, and this number of mice that could be sufficient was chosen in order to ensure that our presented work will achieve better results. This mentioned number of mice was divided into three targeted groups (n=11 each). The first targeted group of mice was kept as unirradiated control in order to compare the results of other groups of mice irradiated with laser with that of the unirradiated control group of mice. Both second and third targeted groups of mice that constitute irradiated groups with laser were anaesthetized and exposed to a low power gallium aluminum arsenide laser (Ga Al As) of wavelength (lambda = 830nm). The beam of mentioned laser was directed above the heart (location of the thymus gland) of the targeted mice and the object was one centimeter distant from the laser source. Once daily irradiation with laser was performed for 30 and 35 minutes to the targeted mice which included both second and third irradiated groups respectively.
The entire period of experimentation (laser irradiation) lasted 12 consecutive days. Both time of receiving laser irradiation and entire period of experimentation (laser irradiation) were arranged for each irradiated group of mice as in the following table:
After the end of the entire period of experimentation (laser irradiation), all the mice including both normal control group and the other irradiated groups were killed and their thymus glands were rapidly obtained. Sections of thymus glands were prepared by using a routine procedure aiming at studying the histological evaluation of the thymocyte composition by light microscopy. Photographs were made at original magnification.
Results
The findings of our experimental work confirmed the existence of marked effects of soft laser on the composition of the thymocytes. These marked effects comprehend as arranged in the following table:
Discussion
The present experimental study represents a hypothesis that established possible effects of laser irradiation when applied to a normal tissue such as the architecture of the thymus gland of mice. So, our findings proved this hypothesis and the laser caused remarkable alterations in the cellular composition of the thymus gland especially the thymocyte architecture. In the second group of mice irradiated with laser for 30 minutes once daily during the entire period of experimentation (12 consecutive days), the laser was effective and caused alterations in the composition of the thymocytes of the thymus glands which were abundant and included increased size of the thymocytes and multiplication of the cellular nuclei (Image 2) compared with the composition of the thymocytes of the thymus glands of the first unirradiated control group of mice which have normal composition (Image1). Whereas in the third group of mice irradiated with laser for 35 minutes once daily during the entire period of experimentation (12 consecutive days), the laser was more effective and in turn, caused alterations in the composition of the thymocytes of the thymus glands which were more abundant and included increased size of the thymocytes and multiplication of the cellular nuclei (Image 3) compared with the composition of the thymocytes of the thymus glands of the second group of mice irradiated with laser (Image2). It could be said that these alterations that occurred in the composition of the thymocytes were due to the following:
1. The selective laser of the presented work was suitable for stimulation of the cellular composition of the thymus gland especially stimulation of the composition of the thymocytes.
2. The gradual increasing in times of our doses of laser irradiation were appropriated because these mentioned times gave the laser the opportunity to alter the composition of the thymocytes.
3. The entire period of period of experimentation (laser irradiation) of the presented work which lasted 12 consecutive days was sufficient to achieve noticeable results.
We may offer possible explanations for the alterations induced by soft laser through its effects on cellular composition of the thymus gland especially the composition of the thymocytes. But, in the same time, our results suggest a gain in functional activity termed a successful stimulation of the soft laser to the cellular composition of the thymus gland especially stimulation of the composition of the thymocytes. In another words, soft laser has examined the functional capacity of the thymus gland by altering the composition of the thymocytes using gradual times of receiving laser irradiation. Laser can stimulate cellular functions by applying it at an appropriate dose (15, 16). However, the principles of laser action in both cells and tissues are still not well understood (17).
As seen in table 3 and figure 1 the statistical features (mean, variance, std) of R, G and B bands of 3 images before and after different time of receiving laser irradiation, show no much different values. So the images preserve their main characteristics except the alterations resulted from stimulating state of laser irradiation (18).
Finally, many questions remain unanswered about the mechanism of laser action and its effects on different types of cells and tissues. These questions should be answered with time and careful investigation.
Conclusive Remarks:
• Soft laser was a successful biostimulative tool in proving our hypothesis and caused alterations in the composition of the thymocyte which included increased size of the cell and multiplication of the cellular nucleus.
• Low powered laser, and as a result of allowing for biostimulatory effects will strengthen the functional immune responses of the thymus gland and that, in turn, will quicken the treatment of dangerous diseases especially cancerous diseases.
Conflict
No conflict of interest
