Quantitative Parameters of Rat Liver Mitochondria
in Relation to Age
D. ADAMIKER
Abstract
From 22 5-month-old and 20 24-month-old Sprague-Dawley rats in a total of
21361 hepatic mitochondria the following parameters were determined by means
of electron microscopy: (1) number of mitochondria per unit of sectioned cell area,
(2) area of the individual mitochondrial section and (3) total area of mitochondrial
sections expressed as percentage of the sectioned cell area. In old animals (1) was
significantly higher and (2) significantly lower than in young ones, whereas the
amount of (3) did not differ between young and old animals.
Mitochondria react quickly and sensitively to disturbances from
internal or external causes. In electron microscopy the aspect of mitochondria is a known criterion for the degree of fixation of a tissue [5]. Also in
vivo mitochondria react very sensitively to disturbing influences exerted
by the organism. Very important among them are the metabolic changes
occurring with increasing age [2, 3, 4]. Ageing appears to be the result
of evolutionary and involutionary processes among which involution
eventually prevails. Morphologically, ageing is characterized by three
distinct processes: (a) atrophy of the specific organ tissues, (b) hypertrophy of the connective tissue and (c) deposition of metabolic endproducts.
The important role mitochondria play in the cell and body metabolism
and the decrease of vital functions with age were the reasons for the present
investigation. It was decided to determine electron microscopically in
young and old rats whether there are any age differences in hepatic mitochondria with respect to number, section area and total area.
11 male and 11 female 5-month-old Sprague-Dawley rats (group Y)
as well as 5 male and 15 female 2-year-old rats (group 0) were used for
these investigations. Electron microscopical sections of the livers of these
animals were prepared according to the usual method (i.e. fixation in
Os04-solution, embedding in a polyester resin), sectioned and photographed. The area of certain sectors as well as that of the mitochondria
contained in them were determined planimetrically and the results analyzed
biostatistically:
10'
in Relation to Age
D. ADAMIKER
Abstract
From 22 5-month-old and 20 24-month-old Sprague-Dawley rats in a total of
21361 hepatic mitochondria the following parameters were determined by means
of electron microscopy: (1) number of mitochondria per unit of sectioned cell area,
(2) area of the individual mitochondrial section and (3) total area of mitochondrial
sections expressed as percentage of the sectioned cell area. In old animals (1) was
significantly higher and (2) significantly lower than in young ones, whereas the
amount of (3) did not differ between young and old animals.
Mitochondria react quickly and sensitively to disturbances from
internal or external causes. In electron microscopy the aspect of mitochondria is a known criterion for the degree of fixation of a tissue [5]. Also in
vivo mitochondria react very sensitively to disturbing influences exerted
by the organism. Very important among them are the metabolic changes
occurring with increasing age [2, 3, 4]. Ageing appears to be the result
of evolutionary and involutionary processes among which involution
eventually prevails. Morphologically, ageing is characterized by three
distinct processes: (a) atrophy of the specific organ tissues, (b) hypertrophy of the connective tissue and (c) deposition of metabolic endproducts.
The important role mitochondria play in the cell and body metabolism
and the decrease of vital functions with age were the reasons for the present
investigation. It was decided to determine electron microscopically in
young and old rats whether there are any age differences in hepatic mitochondria with respect to number, section area and total area.
11 male and 11 female 5-month-old Sprague-Dawley rats (group Y)
as well as 5 male and 15 female 2-year-old rats (group 0) were used for
these investigations. Electron microscopical sections of the livers of these
animals were prepared according to the usual method (i.e. fixation in
Os04-solution, embedding in a polyester resin), sectioned and photographed. The area of certain sectors as well as that of the mitochondria
contained in them were determined planimetrically and the results analyzed
biostatistically:
10'