ABSTRACT
Exposure to crowding stress is associated with increased respiratory system morbidity, However, the underlying mechanisms are unclear. Thus, there is a need for more study of this harmful effect. Sulpiride had been shown to have a protective role against crowding stress on other systems but this role was not studied well on the respiratory and cardiovascular systems. Investigating the possible harmful effects of crowding on adult albino rats' lung and heart and the possible protective role of combined sulpiride treatment. The present study was carried out on 24 adult albino rats of local strain weighing 120 +/- 3 g which were randomly divided equally into Group 1[C, untreated negative control], Group 2 [Cr, crowding exposed or positive control] where rats were exposed to crowding in a cage [20x20x20 cm- 6 rats /cage] for 1 month, Group 3[D, sulpiride-treated] where the rats were exposed to sulpiride "0.028 mg/B.W./day" and Group 4 [Cr+D, crowding + sulpiride-treated]. Paraffin sections were prepared for histological, histochemical and morphometric studies. The data were statistically analysed. The rats exposed to crowding only or sulpiride only showed highly significant damaging changes on lung such as thickening in the interalveolar septa and obliteration of the alveoli, inflammatory cells infiltration within the pulmonary interstitium, peribronchiolar infiltration and fibrosis, thickening of the pulmonary blood vessels walls, interstitial collagen fibres deposition and apoptotic cellular changes. On the level of heart, significant decrease in the diameters of the myocardial muscle fibres with focal areas of necrosis, apoptotic changes and increased collagen fibres deposition was marked in sulpiride group. When crowding and sulpiride treatments were combined, the damaging effects were maximized on the lung and heart. These results provided evidence that crowding stress causes obvious lung and heart tissue damages. No protective role for sulpiride was proofed. This is because using sulpiride alone or in combination with crowding showed marked damaging effects on the lung and heart tissues