Anotace:
The aim of this work was to describe the microscopic and submicroscopic changes of the uterus of 20 pinzugus heifers in their postnatal development (12th, 24th and 36th week of age) and in the experimental form of subclinical hypoglycemia. Uterine specimens were obtained from the uterine horns by a vivisection for histological studies. Samples were fixed for light microscopy (LM) in formaldehyde and for scanning by electron microscope (SEM) and transmissive electron microscopy (TEM) in glutaraldehyde. Subsequently, the samples were processed in the usual manner as used in the LM and electron microscopic studies laboratories. The uterus increased to 24th weeks by 19.4 %. The uterine weight decreased significantly (P<0.01) at the time of hypoglycemia (-14.6 %). When the ovarian weight increased (+48.8 %) to 36th week of age, the uterine weight increased by 39.9 %. At the time of hypoglycaemia, the ovarian weight decreased by 4.4 % and the uterine weight decreased by 17.1 %. Endometrial development was mostly pronounced between 12th and 24th week of age (P<0.05). In particular, the superficial (+24.8 %) and glandular epithelium (+25.9 %) developed. Slower development continues up to 36th week, but in animals with hypoglycaemic development it stagnates (-4.1 % and -18.8 % respectively). The nucleo-cytoplasmic ratio was gradually reduced in luminal epithelial cells (N:C 1:3.2 to 1:2.9 respectively) and narrowed in glandular epithelial cells (N:C 1:2.3 to 1:1.7 respectively). A larger decrease was observed in the glandular epithelium. Mitochondria (M) increased the volume in both epithelium types (22.4 % and 28.2 %). In a hypoglycaemia is volume of M low (-18.4 % and -16.2 %). The rough endoplasmic reticulum (rER) increased in volume (+6.5 % and +5.6 % respectively) in both types of epithelial cells. Hypoglycaemia has been shown to decrease the volume of rER approximately equally (-10.9 % and -10.2 %). Macroscopic, microscopic and submicroscopic cell changes of endometrium are described in postnatal development and experimental subclinical hypoglycemia of heifers. There is a clear manifestation of the energy deficit in the retardation of growth and developmental changes.