ABSTRACT
The application of electrical stimulation can lead to a greater and faster increase in the rate of wound healing, especially when applying the cathedral [negative] stimulation for the first week, followed by the anodal [positive] polarity for the rest of the treatment period. The present work aimed to study the effect of polarity reversal of microelectrical current stimulation [MES] on the healing process in an experimentally induced Achilles tendon injury in rats. Forty three male albino rats were used in this study; they were classified into group I [control group] and group II [experimentally injured group], which was further classified into subgroups, I, II, III and IV. Subgroup I represents the injured tendon without MES treatment, whereas subgroups II, III and IV represent the MES-treated ones. The obtained tendon sections were subjected to H and E staining. Masson's trichrome stain, and immunohistochemical staining for alpha smooth muscle actin [alpha SMA], followed by morphometric study and statistical analysis. Subgroup I showed signs of inflammation, a few thin irregularly arranged collagen, active fibroblasts that start to align in rows on the regenerating collagen bundles, and alpha SMA immunoreactivity. In anodal-treated tendons, signs of inflammation had started to disappear; collagen fibers appeared thin and irregularly arranged, active fibroblasts were obviously observed and minimal alpha SMA immunoreactivity were recorded only in subgroup II. Cathodal-treated tendons showed rapid disappearance of cellular infiltration; most collagen fibers appeared regularly arranged with mature fibrocytes in between and multiple avoid alpha SMA immunoreactive myofibroblasts were maximally observed in subgroup II. alpha SMA was suggested to play a role in wound healing due to its high immunoreactivity in myofibroblasts during wound healing. Moreover, the application of electrical stimulation by applying cathodal [negative] stimulation for the first week, followed by anodal [positive] polarity for the rest of the treatment period may lead to better repaired tissue due to myofibroblast directional attraction to the cathode, especially when applied for 4-week duration
Subject(s)
Male , Animals, Laboratory , Electric Stimulation , Achilles Tendon/pathology , Histology , Immunohistochemistry , Rats , MaleABSTRACT
Hypothyroidism and hyperthyroidism are more common in women than in men, and it was reported that thyroid hormones play an essential role in ovarian physiology. This study aimed to simulate the clinical conditions of hypothyroidism and hyperthyroidism in adult female albino rats, and to detect the possible changes in ovarian estrogen and androgen hormone receptors associated with such clinical conditions. This study used 36 adult female albino rats. Rats were divided into three groups, with 1 2 rats each. Rats of the control group received 0.5 ml saline [0.9%] solution once daily. Six rats received the saline orally using a tube, and the other half received it by intraperitoneal injection for 4 weeks. The rats of the hypothyroid group received daily orally a dose of 18.75 mg/kg propylthiouracil dissolved in saline solution for 4 weeks, and the rats of the hyperthyroid group received a daily intraperitoneal dose of 40 microg/kg L-thyroxine dissolved in saline solution for 4 weeks. Vaginal smears were performed at the end of the experiment; only 22 rats coincided the diestrus phase of the cycle, sacrificed and sections were subjected to hematoxylin and eosin and immunohistochemical staining for estrogen and androgen receptors. In the hypothyroid group, few corpora lutea, atretic follicles, and dilated congested blood vessels were clearly seen. In the hyperthyroid group, the ovarian sections showed numerous corpora lutea; atretic follicles and markedly dilated congested blood vessels were also noted. A negative correlation was documented between estrogen receptor and androgen receptor immunoreactivity in the hypothyroid and hyperthyroid groups. This study suggested that thyroid hormones are important to maintain a normal estrous cycle and hence in the regulation of ovarian hormones. The mechanisms by which thyroid hormones influence ovarian function remain to be elucidated. However, it might be through their effect on the aromatase enzyme, which is the key regulator in ovarian hormones production reflected on the level of steroid hormones receptor expression