An injury to the brain may have led to the death of Otzi - the world-famous 5,300-year-old mummy - scientists say.
A research team from the European Academy of Bolzano/Bozen (EURAC), Saarland University, Kiel University and other partners used a pinhead-sized sample of brain tissue from the corpse to arrive at this conclusion.
The well-preserved natural mummy of Otzi, which is also Europe's oldest mummy, was found in September 1991 in the Otztal Alps, near the Similaun mountain and Hauslabjoch on the border between Austria and Italy.
The new study was able to extract and analyse proteins to further support the theory that Otzi suffered some form of brain damage in the final moments of his life.
Two dark coloured areas at the back of the Iceman's cerebrum had first been mentioned back in 2007 during a discussion about the fracture to his skull.
Scientists surmised from a CAT scan of his brain that he had received a blow to the forehead during his deadly attack that caused his brain to knock against the back of his head, creating dark spots from the bruising. Till now, this hypothesis had been left unexplored.
In 2010, with the help of computer-controlled endoscopy, two samples of brain tissue the size of a pinhead were extracted from the glacier mummy.
This procedure was carried out via two tiny (previously existing) access holes and was thus minimally invasive.
Microbiologist Frank Maixner (EURAC, Institute for Mummies and the Iceman) and his fellow scientist Andreas Tholey (Institute for Experimental Medicine, Kiel University) conducted two parallel, independent studies on the tiny bundles of cells.
Tholey's team provided the latest technology used in the study of complex protein mixtures known as "proteomes."
The protein research revealed a surprising amount of information. Scientists were able to identify numerous brain proteins, as well as proteins from blood cells.
Microscopic investigation also confirmed the presence of astonishingly well-preserved neural cell structures and clotted blood cells.
On the one hand, this led the scientists to conclude that the recovered samples did indeed come from brain tissue in remarkably good condition (the proteins contained amino acid sequence features specific to Otzi).
On the other hand, these blood clots in a corpse almost devoid of blood provided further evidence that Otzi's brain had possibly suffered bruising shortly before his death. Whether this was due to a blow to the forehead or a fall after being injured by the arrow remains unclear.
The results of the study are published in the journal Cellular and Molecular Life Sciences.
