Histological study on the effect of heat stress on cardiac muscle of adult male albino rats and the possible role of mast cells

Heat stress causes serious physiological dysfunction that may result in heat related diseases. The cardiovascular system has been considered the primary target of heart stress. The mechanism of heat stress- induced myocardial damage remains unclear. Recent findings indicate that mast cells are not only necessary for allergic reaction, but they also involved in a variety of neuro inflammatory diseases especially those worsened by stress. This work was aimed to study the effect of heat stress on the myocardium of rats and to clarify the possible role of mast cells in this process. This study was performed on 30 adult male albino rats, divided into three equal main groups [10 rats/ each]; the first main group was control, divided into two equal subgroups [5 rats/ each], the first subgroup [A] was negative control, the second subgroup [B] received 1 ml sterile saline I.P daily for 15 days. The second main group was heat-stressed group which was exposed to heat stress [39°C for 2 hours daily] and the third main group was mast cell stabilized group that received 10 mg/kg/b.w of doxantrazole followed by exposure to heat stress [the same as the second main group], half an hour after drug intake. All rats were sacrificed after 15 days and heart sections were processed. Paraffin sections were stained with H and E, masson trichrom [M.T] and toluidine blue for histological study. Other sections were processed for immuno histochemical demonstration of actin and caspase- 3. Other very small pieces of heart sections were processed for electron microscopic study [E.M]. The cardiac muscle of stressed second group revealed focal areas of necrosis, areas of vaculations with loss of characteristic striations and mononuclear cell infiltration. Congestion and extravasation of blood with odema fluid between cardiac muscle fibers were evident. Excessive collagen fibers deposition was also seen. Decreased reaction for actin and strong+ve reaction for caspase-3 in the affected fibers were demonstrated. Moreover hyperplasia and activation with degranulation of mast cells were documented in C.T endomesium. On ultrastructural level, the same group showed disorganized and fragmented microfilaments and mitochondrial changes. Moreover, degranulated mast cells were documented in the C.T endomesium. On the other hand, non of these changes were observed in cardiac muscles of mast cell stabilized group with the exception of slight congestion and minimal fibrosis in the interstitium and perivascular areas at light microscopic level. It is concluded that heat stress induced histological and ultra structural changes in myocardium and these changes could be mast cell mediated. Such study provided further support for the role of mast cells in stress induced myocardial damage and therefore it might provide a novel medical strategy and therapeutic target in management of heat stress induced cardiomyopathy. Furthermore, stress exposure should be avoided or minimized as much as possible to seek for good health

Study of testicular histology and histochemistry of albino rats after cyproterone acetate administration

The search for safe, effective and reversible contraceptive methods for men is an important goal to increase the available choices for couples to regulate their family size.This work was planned to study the histological and histochemical changes in rat testis after administration of cyproterone acetate [C A]; which is potent synthetic antiandrogen. The reversibility of these changes after arrest of the drug had also been studied. Thirty five adult male albino rats were utilized in this study. They were divided into control [14 rats] and treated [21 rats] groups. The control group was administered 1 ml distilled water orally daily. The treated group was subdivided into two subgroups; the 1[st] subgroup [9 rats] was administered CA at a dose of 1 mg /100 gm body, weight/day orally for one month. Three rats were sacrificed after that period and the others [6 rats] were further subdivided into 2 groups and left without treatment for one and two months. The 2[nd] subgroup [12 rats] was administered the same dose of the drug for two months. Three rats were sacrificed after that period and the others [9 rats] were further subdivided into 3 groups and left without treatment for one, two and three months. At the end of the estimated periods, testicular specimens were processed for histological and histochemical studies. Results revealed that CA produced degenerative changes in the testes in the form of disorganization, exfoliation of the spermatogenic cells and tubular shrinkage together with hyperplasia of the interstitial cells and congestion of the vasculature. An increase in PAS +ve reaction and decrease in methyl green-pyronin reaction were observed. These changes were time dependant and reversible 3 months after arrest of the treatment. It is concluded that CA could be used as reversible male contraceptive drug for short period of time. However, studying its effect on male fertility for long period of time in combination with androgen ester together with frequent assessment of serum testosterone is recommended

Role of zinc administration on the effect of lead on the ovary of adult female albino rats. Histological and histochemical study

The risk of lead exposure and lead poisoning has been a major area of concern for several years mainly for women in both industrialized and developing counteries. The present study was designed to investigate the effect of chronic lead exposure on the ovary of adult female albino rats, and the role of zinc supplementation. Thirty adult female virgin albino rats were utilized in this study. They were classified into three equal groups, the 1[st] group was administered 1ml dist. Water orally and served as control group. The 2[nd] group [Lead - treated group] was administered lead acetate at a dose of 50 mg/kg b.wt. orally. The 3[rd] group [Zinc - supplemented group] was administered lead acetate as in tile 2[nd] group and zinc sulphate at a dose of 1mg /kg b. wt. orally. At the end of three months, animals were killed and ovaries were dissected out, fixd in 10% formol saline and processed for histological and histochemical studies using Hx, E, Masson Trichrome, PAS and Methyl Green and Pyronine stains. Tile histological and histochemical results revealed that chronic lead exposure resulted in degenerative changes in the ovaries and these changes were ameliorated with coadministration of zinc. This protective effect of zine could be attributed to differential distribution of lead, either because of competition between lead and zinc or displacement of lead by zinc