Abstract Normal male

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 (11 mice/group). The first group was kept as a control and was not subjected to laser radiation. The other groups were used subjected to laser beam. The presented study was considered to establish the possible effects of low laser at the cellular structure of the common thymus gland in mice. The outcomes of our work demonstrate the supposition and the laser caused marked changes in the cellular consists of the thymus gland particularly the thymocytes which raised volume of the thymocytes and reduplication of the cellular nuclei. These differences were numerous in the contains of the thymus gland thymocytes of the second group of mice irradiated with laser, but the mentioned alterations were more numerous in the components of the thymocytes of the thymus glands to the last group of mice exposed to laser.

Key Words: Medical Laser, Thymocytes of the thymus gland, Histological alterations, Mice.

Usually the location of thymus in the mediastinum (1, 2). It is build from twice lobes that separated into many lobules; each one is split up from the other by trabeculae that build from connective tissue. Every lobule consists of two main components, an external cortex and an internal medulla (3). The cortex and the medulla meet at region called corticomedullary junction (CMJ) which is considered as the tip of entrance and the way out to develop thymocytes (4). T cell precursors come into presence in the bone marrow and circulating to break the thymus by the corticomedullary cross, and through the intra-thymic trip, T cells usually termed thymocytes (5-8). In thymus and throughout the development, growing thymocytes shift from cortex to medulla (9-11). It shouldn’t be beglect the generating of T cells by thymus through the life span (12, 13). In addition to the greater composition of thymocytes, the thymus microenvironment has different kinds of thymic epithelial cells (TEC), stroma cells, macrophages, fibroblasts and dendritic cells. All these cells contribute in thymocyte maturation process (3).
Corpuscles thymic medulla (Hassall) has different dimensions and contains large sum of thymic epithelial cells (TECs). Those cells secrete many cytokines that are significant for the control of the activity of dendritic cells as well as the differentials of approval T cells (2).
Laser phototherapy has a main role in the medical fields including: promoting wound healing, tissue repair and prohibition tissue from 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 structure of the thymus gland particularly 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:

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:

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:

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 goals for this empirical research, 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.

The findings of our experimental work confirmed the existence of marked effects of soft laser on the thymocytes structure. These marked effects comprehend as arranged in Table1, Table 2 and Table 3.

The current experimental study perform a hypothesis that established probable effects of laser irradiation when utilized to a normal tissue like the thymus gland structure of mice. So, our feedback proved this hypothesis and the laser caused notable changes in the cellular structure of the thymus gland particularly the thymocyte structure.
In the subsequent 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 result in structure changes of the thymocytes of the thymus glands which were abundant and inclusively rise the volume of the thymocytes and duplication of the cellular nuclei (Image 2) analogy with the thymocytes glands structures. The first unirradiated (control group) of mice which have normal composition (Image1). while in the third group of mice irradiated with laser for 35 minutes once daily during the entire period of experimentation (12 sequential days), the laser was more effective and in turn, caused changes in the composition of the thymocytes of the thymus glands which were more abundant and included enlarged size of the thymocytes and duplication 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 occur 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 particularly stimulation of the thymocytes components

2. The steady increasing in times of our doses of laser irradiation were appropriated because these mentioned times gave the laser the opportunity to alter the thymocytes components.

3. The total period time 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 component of the thymus gland especially the component of the thymocytes. However, in the same time, our results suggest a gain in functional activity termed a successful stimulation of the soft laser to the cellular component of the thymus gland particularly stimulation of the composition of the thymocytes.

In another words, soft laser examined the efficient ability of the thymus gland by altering the component of the thymocytes using regular 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 each cell and tissues are still not well known (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 diverse sorts of cells and tissues. These inquires should be answered through time and careful investigation.

Conclusive Remarks:
• Soft laser was a successful biostimulative tool in proving our hypothesis and reflect to the changes the hymocyte structure which has raised the cell dimensions as well as duplication of the cellular nucleus.
• Low energy laser, and as a consequence of allowing for biostimulatory effects will reinforce the functional immune reactions of the thymus gland and that, in turn, will quicken the treatment of dangerous diseases especially cancerous diseases.

No conflict of interest