Positive Health Online

Abstract

Chen, Li and Liu, Cancer Institute (Hospital), Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing. investigated the effect of ascorbate on the permeation and photosensitizing activity of hematoporphyrin derivative (HPD) in tumour

Background

Methodology

Solid S-180 sarcoma of 1 cm3 in size was excised from tumour-bearing mice and immersed in HPD (PsD-007) 1 mg/ml normal saline (group I), or HPD (PsD-007) 1 mg/ml plus ascorbic acid 20 mg/ml normal saline (group II) for 1 hr. For comparison, HPD (PsD-007) 10 mg/kg was injected intravenously to mice bearing tumour of similar size and the tumour was excised 24 hr later(group III).

Results

Tumours were cross-sectioned and UV (370 nm) irradiated, red fluorescence was mainly at the periphery of tumours that had been immersed in HPD whereas the fluorescence was weaker and more evenly distributed in tumours of mice that had received HPD i.v. Similar features were observed under fluorescence microscope in frozen sections of identically treated tumours. The concentration of PsD-007 (microgram/g) and malondialdehyde (nmol/L) in the tumour homogenates was higher in tumours that had been immersed in PsD-007 plus ascorbate than in tumours immersed in PsD-007 alone. Tumours of mice that had received PsD-007 i.v. had the lowest concentration of both PsD-007 and malondialdehyde.

Conclusion

Ascorbate facilitates permeation of HPD into tumour and enhances the photo-dynamic effect of HPD .

References

Chen Y et al. Effect of ascorbate on the permeation and photosensitizing activity of hematoporphyrin derivative (HPD) in tumour. Chung Hua Chung Liu Tsa Chih 19(5): 350-2. Sep 1997.