Abstract

ABSTRACT Background: It is well known that heat stress produces liver injury. It is also known that liver regenerate after injury. This way, there should be almost no or minimal alteration in the size of the liver after regeneration. Aims &
Objective: In the present study, after heat induced liver injury, the ability of liver to regenerate itself was assessed. Liver injury was assessed by biochemical [Serum Glutamic Pyruvate Transaminase (SGPT); Serum Glutamic Oxaloacetic Transaminase (SGOT); and Alkaline Phosphatase (ALKP)], morphological, and morphometric changes. On the other hand, Liver regeneration was evaluated by morphological and morphometric observations of male adult albino rats (Wistar strain). Material and Methods: The experimental animals were subjected to repetitive heat stress for 4 hours daily, at 37 ± 0.5 ˚C in a Biological Oxygen Demand (BOD) incubator (relative humidity 65 - 82%) for 2 and 5 consecutive days. Biochemical assessment was done on blood collected from left ventricle of beating heart of rats. Morphometric and morphological studies were conducted under light microscope on paraffin sections (H&E) of liver from control and experimental animals. The morphometric analysis was done by intersection – point counting method, using simple square lattice test system. Relative Liver Wet Weight of all animals was calculated.
Results: Progressively degenerative changes in morphological observations (disruption of cell plates in liver lobules and Kupffer cell hyperplasia), progressively increased statistical significance of morphometric (numerical density of Kupffer cells on area - Nak), and biochemical parameters informed that increasing liver damage was present with increased repetition of heat exposures in 2 and 5 days heat exposed experimental albino rats. With this liver degeneration, Relative Liver Wet Weight of all the experimental animals should have been decreased but it was not, reiterating about well-known fact of regenerative ability of liver. Along with progressive changes of heat induced liver injury, progressively increasing regenerative changes were also evident on morphological (binucleate cells and anisocytosis) observations supported by statistically significant morphometric (volume density of hepatocytes – Vvh and numerical density of hepatocytes - Nvh) parameters in experimental animals. Conclusion: The above findings suggested that the regenerative ability of liver progressively increased with progressively increasing liver injury.