Effect of Time Restricted Feeding and its Endocrine Regulation in Hepatectomized Fibrotic rats-A Histomorphological and Biochemical Study

Abstract

Owing to the numerous vital responsibilities granted to the liver, nature has imparted this organ the ability to regenerate in order to safeguard the functions performed by it. Hepatic regeneration is a remarkable physiological process with marvelous highly coordinated biological events that occur simultaneously and sequentially leading to the hypertrophy and hyperplasia of hepatocytes allowing the liver to regenerate to its original size following resection. In contrast to the normal liver fibrotic liver showed delayed and impaired regenerative response because of slow proliferation rate and increased extracellular matrix. Hepatocyte mitosis, trophic state and fibrosis are influenced by circadian clock oscillations. Circadian rhythms in the body are entrained by two important zeitgebers namely light and feed. Light is the dominant zeitgeber of the central master clock residing in the suprachiasmatic nucleus (SCN) while peripheral clocks are mainly influenced by feeding patterns viz. caloric restriction, intermittent fasting and time restricted feeding (tRF). The tRF is the only pattern that entrains peripheral clocks independent of SCN, especially the hepatic clock. Present study has been conducted to evaluate the effect of time-restricted feeding on the regeneration ability of liver following partial hepatectomy. Animals were made fibrotic by eleven weeks intragastric carbon tetrachloride treatment while vehicle received olive oil. Each group was then either fed ad libitum or subjected to two weeks of time-restricted feeding i.e. time-restricted fed for 12 hours when the light was on (tRF1) and time-restricted fed for 4 hours only after 4hrs of light on and before 4hrs of light off (tRF2), before undergoing two-third partial hepatectomy (PHx). Liver regenerative capacity, functional capability along with hepatic antioxidant and mineral content was evaluated 48 hours post PHx. Finally adrenal and thyroid hormones concentrations, being the most influential hormones on liver have also been determined. The tRF schedules markedly decreased the body weights of rats and recovered them significantly after PHx especially the full daytime feed restriction. Liver regeneration as assessed by estimating different somatometric, hypertrophic and hyperplasic estimates xiii indicated no effect of tRF on relative liver weight. However, liver regeneration rate was significantly increased by both feeding regimens specially the first schedule. The tRF regimen inhibited hyperplasia as percentage proliferation cell nuclear antigen and mitotic count were reduced by the treatments. The restricted feeding schedules did not affect AgNOR index in vehicle rats, however, fibrotic rats showed increased and heterogeneous AgNOR index when the feed was restricted to middle of the light phase. Both feed restriction schedules increased the binuclear cells that were decreased significantly during the regenerative process. A marked reduction in hepatocyte cellular area under temporal feed restriction was observed that remained restricted after PHx compared to ad libitum fed rats. Nuclear morphometry also followed the same trend in vehicle rats but fibrotic rats remained non-responsive to tRF regimens. Hepatic tissue analysis showed that tRF regimens increased the hepatic water, lipid and glycogen content with no effect on DNA and protein. Hepatic functional capability evaluation indicated improvement in serum alanine transaminase and aspartate transaminase under tRF regimens with no significant effect on alkaline phosphatase, bilirubin, total protein and albumin levels. Lactate dehydrogenase activity was significantly restored in vehicle rats while glucose and triglyceride were differentially affected by temporal feeding restrictions. Decreased serum glucose under tRF1 while increased triglyceride levels under tRF2 in fibrotic rats was observed. Temporal feed restriction decreased the extra cellular matrix in vehicle rats with little or no improvement in fibrotic rats as indicated by hydroxyproline quantification and histopathological evaluation by Gomori triple stain and α-SMA. Serum corticosterone levels were increased by partial hepatectomy. Timed-feed restriction had a differential effect on corticosterone concentrations with no effect on vehicle rats while a considerable decrease and increase under the first and second regimen respectively was observed in fibrotic rats. Partial hepatectomy depressed the thyroid hormone levels which were raised by time-restricted feeding in vehicle and fibrotic rats under the first and second schedule respectively by significantly increasing serum thyroxine levels. Serum triiodothyronine/thyroxine ratio was considerably low in these xiv rats. Significantly reduced triiodothyronine and triiodothyronine/thyroxine ratio in fibrotic sham livers were remarkably increased by second schedule after partial hepatectomy. The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while The tRF treatments improved the hepatic catalase levels in both groups while peroxidase and superoxide dismutase levels dlevels dlevels d levels d levels did not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the id not show any significant effect under the treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but treatments. No decrease in hepatic thiobarbituric acid reactive substance levels but significant increase in significant increase in significant increase in significant increase in significant increase in significant increase in significant increase in significant increase in significant increase in significant increase in glutathione content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly content under the tRF regimens was seen. Interestingly glutathione peroxidase levels were levels were levels were levels were levels were increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats increased and decreased in vehicle fibrotic rats respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. respectively under the first feeding schedule. Glutathione reductase activity was activity was activity was activity was activity was activity was activity was activity was activity was significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF significantly increased in vehicle rats with no effect on fibrotic under the second tRF regimen. regimen. regimen.regimen. No significant change in hepatic sodium and potassium contents were observed except a considerable decrease under tRF2 in vehicle rats that tend to raise their levels during the regenerative process. Interestingly the first feeding regimen elevated while the second has depressed the hepatic magnesium levels during regeneration. Calcium and iron was non-significantly decreased in vehicle rats under the tRF treatments while copper was significantly reduced in control animals with a rise in fibrotic livers under the second regimen. Zinc was raised in fibrotic rats under the treatments. Temporal feed restriction influenced liver regeneration by inhibiting hyperplasia, producing a shift from hepatocyte binuclearity to mononuclearity, reducing ploidy and hypertrophy, effecting hepatic tissue constituents, and lipid related metabolic events. The tRF regimens improved the hepatic functional and antioxidant capacity; and mineral metabolism during regeneration. Temporal feed restriction had produced different alterations in adrenal and thyroid hormones with respect to vehicle and fibrotic rats, which further influence liver regeneration being bound in a complex close relation with liver.