Vitamin B₁₂ supplement alleviates N′-nitrosodimethylamine-induced hepatic fibrosis in rats

Abstract

Context: Altered vitamin B₁₂ levels have been correlated with hepatotoxicity; however, further evidence is required to establish its protective role.

Objective: To evaluate the effects of vitamin B₁₂ supplement in protecting N′-nitrosodimethylamine (NDMA)-induced hepatic fibrosis in Wistar rats.

Materials and methods: Hepatic fibrosis was induced by administering NDMA in doses of 10 mg/kg body weight thrice a week for 21 days. Another group received equal doses (10 mg/kg body weight) of vitamin B₁₂ subsequent to NDMA treatment. Animals from either group were sacrificed weekly from the start of the treatment along with their respective controls. Progression of hepatic fibrosis, in addition to the effect of vitamin B₁₂, was assessed biochemically for liver function biomarkers, liver glycogen, hydroxyproline (HP) and B₁₂ reserves along with histopathologically by hematoxylin and eosin (H & E) as well immunohistochemical staining for α-SMA expression.

Results and discussion: Elevation in the levels of aminotransferases, SALP, total bilirubin and HP was observed in NDMA treated rats, which was concomitant with remarkable depletion in liver glycogen and B₁₂ reserves (p < 0.05). Liver biopsies also demonstrated disrupted lobular architecture, collagen amassing and intense fibrosis by NDMA treatment. Immunohistochemical staining showed the presence of activated stellate cells that was dramatically increased up to day 21 in fibrotic rats. Following vitamin B₁₂ treatment, liver function biomarkers, glycogen contents and hepatic vitamin B₁₂ reserves were restored in fibrotic rats, significantly. Vitamin B₁₂ administration also facilitated restoration of normal liver architecture.

Conclusion: These findings provide interesting new evidence in favor of protective role for vitamin B₁₂ against NDMA-induced hepatic fibrosis in rats.

• α-smooth muscle actin
• hepatoprotection
• hepatic stellate cells
• liver fibrosis
• liver function biomarkers

Acknowledgements

This work is supported by grant [INSPIRE Fellowship (IF10293)/ DST], awarded to AA by DST, Ministry of Science & Technology, New Delhi. The authors sincerely thank the Chairman, Department of Zoology, for providing necessary facilities and to Prof. Veena Maheshwari, Department of Pathology, JNMC, for generously extending the microscopy facility. We are obliged to Dr. Absar-ul Hasnain, Department of Zoology, Aligarh Muslim University, for significant and necessary suggestions that helped in improving the manuscript. We also acknowledge timely help of Mr. Rashid Saleem and Mr. Mukhtar Alam for performing few biochemical estimates of our samples.