Fourier Transform Infrared Spectroscopy Reveals Molecular Changes in Blood Vessels of Rats Treated with Pentadecapeptide BPC 157
Ozren Gamulin, Katarina Oroz, Luka Coric, Maria Krajačić, Marko Škrabić, Vilim Dretar, Sanja Štrbe, Jasminka Talapko, Martina Juzbašić, Ivan Krezić, Marin Lozić, Vasilije Stambolija, Helena Žižek, Ivana Jurca, Ivana Jurjević, Alenka Boban Blagaić, Anita Škrtić, Sven Seiwerth, Predrag Sikirić
Abstract
Recently, it was found that when confronted with major vessel occlusion and vascular failure, stable gastric pentadecapeptide BPC 157 therapy might rapidly functionally improve minor vessels to take over the function of disabled major vessels, reorganize blood flow, and compensate failed vessel function. We focused on the BPC 157 therapy effect obtained by giving 10 ng/kg ip to rats 5 min before sacrifice on the rat thoracic aorta, which we assessed with Fourier transform infrared spectroscopy (FTIR) 90 min thereafter. We applied a principal component analysis (PCA). The PCA model showed, with a clear distinction being mostly due to the PC1 score, differences between the spectra of BPC 157- and saline-treated rats. The comparison of the averaged spectra of these two groups with their differential spectrum and PC loadings allowed us to identify the parts of the FTIR spectra that contributed the most to the spectral separation of the two observed groups. The PC1 loadings and the differential spectrum showed that the main bands affecting the separation were the amid I band around 1650 cm−1, the amid II band around 1540 cm−1, and the vibrational band around 1744 cm−1. Fitting the spectral range between 1450 and 1800 cm−1 showed changes in protein conformation and confirmed the appearance of the vibrational band at 1744 cm−1. Controls had a substantially more intense vibrational band at 1744 cm−1. These spectral results showed the cells from saline-treated (control) rats to be in the early stage of cell death, while the samples from BPC 157-rats were protected. Thus, BPC 157 therapy changed the lipid contents and protein secondary structure conformation, with a rapid effect on vessels, within a short time upon application.