Washington: An injury to the head and not an arrow wound, may have killed Otzi the Iceman, the 5,300-year-old mummy found in the Italian Alps, a new paleoproteomic study suggests.
The protein investigation appears to support a 2007 research into Europe`s oldest natural human mummy`s brain. The study pointed to a cerebral trauma as the cause of death.
At that time, the research relied on a CAT scan of the mummy`s brain which showed two dark coloured areas at the back of the cerebrum. The injury added to the already known arrowhead wound on the shoulder and wounds on the hand.
Found in Otzi`s left shoulder in 2001, the stone arrowhead has long been thought to have caused the prehistoric man`s death, fatally severing his left subclavian artery, Discovery News reported.
The 2007 study suggested that blood loss from the arrow wound would have first made Otzi lose consciousness, with death coming later, from a violent blow to the head.
Either the man`s killer gave Otzi the final whack, possibly by hitting him with a stone, or he could have fallen over backwards and hit his head on a rock, the researchers concluded.
The hypothesis had been left unexplored until 2010, when a research team from the European Academy of Bolzano/Bozen (EURAC), Saarland University, Kiel University and other partners decided to investigate the proteome of two pinhead-sized samples of brain tissue from the world-famous glacier corpse.
"The use of new protein-analysis methods has enabled us to pioneer this type of protein investigation on the soft tissue of a mummified human, extracting from the tiniest sample a vast quantity of data which in the future may well answer many further questions," the researchers said.
Indeed, the scientists were able to identify a total of 502 different proteins.
"Of these, 41 proteins are known to be highly abundant in brain tissue and 9 are even specifically expressed in the brain," microbiologists Frank Maixner of EURAC, Andreas Tholey of Kiel University, and colleagues wrote.
"Furthermore, we found 10 proteins related to blood and coagulation. An enrichment analysis revealed a significant accumulation of proteins related to stress response and wound healing," they wrote.
Found in a corpse almost devoid of blood, the astonishingly well-preserved clotted blood cells provide 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 findings are published in the journal Cellular and Molecular Life Sciences.